副業

日本副業經費與報稅指南 2026 — 避免公司察覺

在日本經營副業的同時避免被公司察覺：經費管理技巧、青色申告選擇、住民稅普通徵收切換、20 萬日圓申報規則與節稅要點一次講清，讓副業更安心。

2026年1月1日

|Source:國稅廳

僅供一般參考。個人稅務建議請諮詢專業人士。最後驗證日期: 2026年1月1日 · 來源: 国税庁

這是為全職工作同時有副業的人士準備的費用管理指南。正確申報費用可以獲得稅收優惠，但也要了解如何保護隱私不讓雇主發現。

報稅門檻

對於工資收入者，如果副業收入超過每年20萬日圓，則需要報稅。但是，即使低於20萬日圓，住民稅申報仍然是必需的。

如何保持副業隱私

Choose "Direct Payment" for Residence Tax重要

By selecting "Self Payment" in the residence tax section of your tax return, your side income tax will not be notified to your employer.

Check Company Regulations

Check if side jobs are prohibited. If permission is required, consider applying formally.

Avoid Competing with Main Job

Side jobs competing with your main job may violate regulations. Also avoid using main job information.

Understand the ¥200,000 Rule重要

Even if side income is under ¥200,000/year, residence tax filing is required. File with your local municipality even if income tax filing is not needed.

可抵扣的副業費用

Computer & Equipment

可抵扣

+Computer/tablet (business dedicated)
+Monitor and keyboard
+Camera and microphone (for streaming/recording)
+Software and subscriptions

不可抵扣

-Computer shared with personal use (full amount)
-Gaming/entertainment equipment

提示: Prorate by business use if shared. Under ¥100k is immediate expense, Blue Return allows up to ¥300k.

Workspace

可抵扣

+Rent (business use area)
+Electricity (business portion)
+Internet (business portion)
+Coworking space fees

不可抵扣

-Mortgage principal
-Personal portion of utilities

提示: If working from home, prorate by floor area. Typically 20-40% is common.

Communication

可抵扣

+Mobile phone charges (business portion)
+Video conferencing tools (Zoom, etc.)
+Cloud storage
+Domain and hosting fees

不可抵扣

-Personal call charges
-Entertainment subscriptions

提示: If shared between business and personal, prorate by call logs or usage time. Typically 30-50%.

Learning & Skills

可抵扣

+Business-related online courses
+Professional and technical books
+Business-related certification costs
+Seminar and conference fees

不可抵扣

-Hobby classes
-Unrelated certifications
-Entertainment books

提示: Relevance to your side job is key. Fully deductible if you can explain the business connection.

報稅準備清單

Organize Your Income

Get annual payment statements from each platform
Check bank account deposit records
Collect withholding tax slips (if any)

Calculate Your Expenses

Organize receipts by expense category
Record calculation basis for prorated expenses
Also use credit card statements

Prepare Tax Return

Use the NTA tax return preparation site
Combine salary income and business (miscellaneous) income
Select "Self Payment" for residence tax

File and Pay

Online filing via e-Tax is recommended
Deadline is March 15 (income tax)
Pay by bank transfer or credit card before deadline

別忘了選擇住民稅

如果不在報稅單的住民稅相關事項中選擇「自行繳納」，您的雇主將會被通知。

常見問題

The most common cause is residence tax. If you leave the payment method as "Special Collection (payroll deduction)" when filing, your employer receives notification of residence tax including side income, which payroll staff may notice. By selecting "Direct Payment (self payment)", you pay side income tax directly and it is not notified to your employer.

Income tax filing is not required, but residence tax filing is. If you neglect residence tax filing, you may face additional taxes later. Either file directly with your municipality, or file income tax return (which automatically files residence tax). Also, if you want medical expense or furusato deductions, income tax filing is required even under ¥200,000.

Yes, if you work on your side job at home, you can claim part of your rent as an expense. Calculate by floor area. For example, if using 6㎡ for work in a 30㎡ room, 20% of rent can be expensed. Keep records of your calculation basis.

It depends on the scale of your side job. If you have continuous income at a certain level (roughly ¥1M+ annually), Blue Return is beneficial. You get a ¥650,000 special deduction and can carry forward losses. However, it requires double-entry bookkeeping. For small side income, White Return is fine.

費用檢查工具

即時檢查費用是否可抵扣。顯示類別和抵扣率的免費工具。