一人親方でもインボイス対応の請求書が必要ですか？

取引先が課税事業者（法人や元請け）の場合、適格請求書（インボイス）を求められることが多いです。登録番号・税率ごとの消費税額を記載できるソフトを使えば自動で対応できます。

無料の請求書ソフトではだめですか？

無料プランは月の発行枚数制限（例: 月5〜10枚）や機能制限があることが多いです。月10件以上仕事がある一人親方なら、月額2,980円程度の有料プランの方が結果的に時間の節約になります。

経費の記録はどうするのが楽ですか？

レシートをスマホで撮影してAI-OCRで読み取る方式が最も楽です。金額と日付が自動入力されるので、手入力はほぼ不要になります。

How sole contractors can finish their paperwork for ¥2,980 a month | Real examples of estimates, invoices and expenses

Published: 2026-07-21 / Author: Akio Nojima (handyman & well driller / owner of Nojima Giken)

Paperwork for sole contractors and sole proprietors can be streamlined perfectly well with cloud software under ¥3,000 a month. In this article, the author, who runs a handyman and well-drilling business, shows how he actually handles estimates, invoices, receipts, customer management and expense records for ¥2,980 a month.

Sole contractors' paperwork: what should you pay for, and how much?

In short, a sole contractor doing field work needs only these five things.

Creating estimates, invoices and receipts (qualified-invoice compliant)
Managing customer information (address, phone, past jobs)
Managing the work schedule (calendar)
Recording expenses (just snap receipts with your phone)
Storing job photos (by site and by document)

Major accounting software adds journal-entry and year-end closing features and costs ¥2,000–3,000 a month, but tax returns are once a year. If you focus on the five things above that daily work needs, it can be much cheaper.

Real example of business management for ¥2,980 a month

Task	The old way	After adopting software
Creating estimates	Open an Excel template, copy and edit (15 min)	Select the customer and enter line items (3 min). With voice input, done in the car
Creating invoices	Open the estimate and copy it over (10 min + risk of mistakes)	Convert from the estimate in one click (10 sec)
Checking payments	Match the bankbook against invoices	Show only "unpaid" in a list
Finding old documents	Dig through folders (minutes — or never found)	Search by customer name (seconds)

Three criteria for choosing software

1. Can you do everything on a smartphone?

For field work, going back to the office is a waste of time. What matters most is being able to create an estimate on a smartphone or tablet and show it to the customer on the spot.

2. Are estimates, invoices and receipts connected?

Separate software for each document leads to copying mistakes. Choose one where everything is connected in a single flow.

3. Is it ¥1,000 a month or less?

¥3,000 a month is overinvesting for a sole contractor's admin work. It adds up to a difference of ¥20,000–30,000 a year.

The software the author uses

Commercial software didn't fit the reality of field work, so the author developed his own business management software, Flexsys, and uses it every day in his handyman and well-drilling business. At ¥2,980 a month (up to 30 users) it covers all five tasks above, with a 90-day free trial (no card required).

FAQ

Q. Do sole contractors also need qualified invoices?A. If your client is a taxable business (a corporation or main contractor), you will often be asked for a qualified invoice. Software that can show your registration number and consumption tax by rate handles it automatically.

Q. Isn't free invoicing software good enough?A. Free plans often limit how many documents you can issue per month (e.g. 5–10) or restrict features. If you have 10 or more jobs a month, a paid plan around ¥2,980 a month ends up saving you time.

Q. What is the easiest way to record expenses?A. Photographing receipts with your smartphone and reading them with AI-OCR is the easiest. The amount and date are filled in automatically, so there is almost no manual entry.