--- title: "MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm" canonical: "https://stationerytimes.com/guides/muji-oil-ink-polycarbonate-ballpoint-pen/" description: "MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm explained: 14.0 cm long, 1.5 cm across, water-resistant oil ink, black and red, refills, price band and origin." category: "Pens" type: "Ballpoint pen" published: 2026-11-01 updated: 2026-11-01 author: "Ellis Penhale" publisher: "Stationery Times" sources: 3 products: - name: "MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm" brand: "MUJI" brand_origin: "Japan" made_in: "Japan" material: "Polycarbonate and elastomer (per MUJI USA)" price_band: "$ (under $5 per pen (multi-packs divided by the count), typical US retail, October 2026)" manufacturer: "Ryohin Keikaku Co., Ltd." model: "Oil Ink Polycarbonate Ballpoint Pen 0.7mm" gtin: "4548718444434" url: "https://www.muji.us/products/oil-ink-polycarbonate-ballpoint-pen-0-7mm-s444" --- # MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm > The MUJI Oil Ink Polycarbonate Ballpoint Pen is a simple 0.7 mm ballpoint with a polycarbonate body. MUJI USA lists it at 14.0 cm (5.5 in) long and 1.5 cm across, says the oil ink withstands a light wash, sells it in black and red, and gives Japan as the origin. - URL: https://stationerytimes.com/guides/muji-oil-ink-polycarbonate-ballpoint-pen/ - Category: Pens - Author: Ellis Penhale - Published: 2026-11-01 - Updated: 2026-11-01 ![MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm drawn to scale at 14.0 cm long and 1.5 cm across with a pocket clip](https://stationerytimes.com/images/raster/muji-oil-ink-polycarbonate-ballpoint-pen-illustration-16x9.png?v=c7d7b453) *The pen at MUJI USA's listed 14.0 cm by 1.5 cm (1 mm = 6.25 px).* Original illustration made for this guide. © Stationery Times. Original drawing (SVG): . Drawings © 2026 Stationery Times, reusable with credit under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ## Product facts | Product | Brand | Brand origin | Made in | Material | Released | Price range (typical US retail, October 2026) | |---|---|---|---|---|---|---| | MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm | MUJI (by Ryohin Keikaku Co., Ltd.) | Japan | Japan | Polycarbonate and elastomer (per MUJI USA) | – | $: under $5 per pen (multi-packs divided by the count) | - Made in (MUJI Oil Ink Polycarbonate Ballpoint Pen 0.7 mm): Japan. MUJI USA's product details give "Country/Region of Origin: Japan". Source: https://www.muji.us/products/oil-ink-polycarbonate-ballpoint-pen-0-7mm-s444 - Good for: Everyday writing. ## Key takeaways - MUJI USA lists the pen at 14.0 cm (5.5 in) long and 1.5 cm (0.6 in) across, with a 0.7 mm tip. - The body is polycarbonate with an elastomer part; the ink is oil-based. - MUJI says the oil ink can withstand a light wash and suits multi-media sketches; that is a maker claim, not our test. - Two colors in the US: black and red, and MUJI sells matching 0.7 mm refills. - MUJI USA gives Japan as the origin, and each pen is in our $ band (under $5). ## What is the MUJI Oil Ink Polycarbonate Ballpoint Pen? **It's a plain ballpoint with a 0.7 mm tip and an oil-based ink, sold by MUJI in black and red.** MUJI USA describes it as a simple pen for everyday use. MUJI is the brand of Ryohin Keikaku, the Japanese retailer. The barrel is unusually thick for a pen this plain: 1.5 cm across, per MUJI USA. That helps people who find slim pens tiring. ## MUJI oil ink ballpoint specs | Spec | Value | |---|---| | Maker | MUJI (Ryohin Keikaku Co., Ltd.), Japan | | Type | Ballpoint pen, refillable | | Length | 14.0 cm (5.5 in) | | Diameter | 1.5 cm (0.6 in) | | Tip | 0.7 mm (about 0.03 in) | | Ink | Oil-based | | Materials | Polycarbonate, elastomer | | Colors (US) | Black, red | | Barcode (black) | 4548718444434 | | Made in | Japan (MUJI USA) | MUJI USA gives no weight, and its listing doesn't say how the pen opens or closes, so the clip and button in our drawing are drawn by eye. ## Who is the MUJI oil ink ballpoint for? **It suits people who want a plain, cheap everyday ballpoint with a thick barrel.** - **Everyday writing:** MUJI USA calls it a simple pen for everyday use, in our $ band, with 0.7 mm refills sold separately. Skip it if you want a fine line: 0.7 mm is the widest ball MUJI sells in its smooth oil ink range. ![Bars at 20 times scale showing 0.38, 0.5 and 0.7 mm nominal ball sizes](https://stationerytimes.com/images/muji-oil-ink-polycarbonate-ballpoint-pen-ball-sizes.svg?v=80701b8c) *This pen's 0.7 mm ball against the 0.38 and 0.5 mm sizes of MUJI's smooth oil ink pens (nominal, at 20×). Original illustration made for this guide. © Stationery Times.* ## Does the oil ink survive water? **MUJI USA says the oil-based ink can withstand a light wash and suits multi-media sketches.** That is a claim about washing over a drawn line, not about soaking. Oil-based ballpoint ink usually sits on the paper rather than soaking in, which is why the maker can say this. We haven't tested it, and the hands-on slot below is where our test will go. ## How do the refills work? **MUJI USA sells a 0.7 mm refill for its polycarbonate ballpoint pens in colors such as blue and red.** It also lists the pen in black and red, so a blue refill gives you a third color in the same body. Check the refill listing for the exact color you want. ## How does it compare with MUJI's other ballpoints? **It's the thickest and the widest-lined; the [smooth oil ink pen](https://stationerytimes.com/guides/muji-smooth-oil-ink-ballpoint-pen/) is slimmer with a grip and three ball sizes.** | | Oil Ink Polycarbonate | Smooth Oil Ink | |---|---|---| | Length | 14.0 cm (5.5 in) | 14.1 cm (5.6 in) | | Ball sizes | 0.7 mm | 0.38 / 0.5 / 0.7 mm | | Ink | Oil-based | Oil-based, quick drying | | Made in | Japan | Japan | For the gel alternatives see MUJI's [gel ink pen](https://stationerytimes.com/guides/muji-gel-ink-pen/) and the roundup of [best ballpoint pens](https://stationerytimes.com/guides/best-ballpoint-pens/). ## Where is it made, and what does it cost? **In Japan: MUJI USA gives Japan as the country or region of origin.** Each pen is in our $ band, under $5. MUJI USA sells it as Final Sale, with no refunds or exchanges; we read the page on November 1, 2026, and prices change. ## Frequently asked questions ### Is the MUJI oil ink ballpoint waterproof? MUJI USA says the oil-based ink can withstand a light wash. That is not the same as waterproof, and we haven't tested it. ### How thick is the MUJI polycarbonate ballpoint pen? MUJI USA lists a diameter of 1.5 cm (0.6 in) and a length of 14.0 cm (5.5 in), which makes it a fairly fat barrel. ### What colors does the MUJI oil ink ballpoint come in? MUJI USA lists black and red. ### Can you refill the MUJI polycarbonate ballpoint pen? MUJI USA sells a Refill for Polycarbonate Ballpoint Pen 0.7mm in colors such as blue and red, so the pen is meant to be refilled. We haven't checked every refill color. ### Is the MUJI oil ink pen made in Japan? Yes. MUJI USA lists Japan as the country or region of origin. ### Does the MUJI ballpoint have a clip or a cap? MUJI USA's listing mentions neither. We drew a clip by eye, so check the product photos before you buy. ### Can I return a MUJI pen bought online? MUJI USA marks it Final Sale, with no refunds or exchanges, on its product page as we read it. ## Sources - [MUJI USA: Oil Ink Polycarbonate Ballpoint Pen 0.7mm (Dia. 1.5 x Length 14.0 cm; tip 0.7 mm; polycarbonate, elastomer; oil-based ink; Japan; black and red; read in full November 1, 2026)](https://www.muji.us/products/oil-ink-polycarbonate-ballpoint-pen-0-7mm-s444) - [MUJI USA: Oil Ink Polycarbonate Ballpoint Pen 0.7mm - Refill - Blue (listing seen in the stationery collection)](https://www.muji.us/products/oil-ink-polycarbonate-ballpoint-pen-0-7mm-refill-blue) - [MUJI USA stationery collection (product list, read November 1, 2026)](https://www.muji.us/collections/stationery)