“〜tsuide ni”: While at It / Taking the Opportunity To [JLPT N4]
Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026
“On my way to the bank, I also dropped by the post office” — efficiently doing a second thing while doing the first
「コンビニに行くついでに、切手を買う」 — 「〜ついでに」, “while I'm at it, on the occasion of”
「コンビニに行くついでに、切手も買ってきて」 (while you're going to the convenience store, buy stamps too) — 「(verb dictionary／た-form・noun の) ＋ ついでに」 means “while at it, taking the chance of doing A, also do B.” The core is “since I'm doing A anyway, I'll do B too.” This guide covers 「ついでに」's attachment, that “while at it” feel, and how it differs from 「ながら (while doing)」.
Core: use the chance of doing A to also do B
「〜ついでに」 = “while at it, on the occasion of,” using the chance of A to also do B:
- Verb ＋ ついでに: 買い物に行くついでに、銀行にも寄る (going shopping, also stop by the bank).
- Noun の ＋ ついでに: 散歩のついでに、パンを買う (on a walk, buy bread).
Point: A is the main purpose, B is incidental (done while at it). There's an order; A usually comes first or simultaneously.
How to Connect
| Form | Attachment | Example |
|---|---|---|
| verb dictionary／た-form | 〜ついでに | 行くついでに |
| noun ＋ の | noun の ＋ ついでに | 買い物のついでに |
| A (main) ＋ B (incidental) | do B while at it | 〜ついでに、B |
Examples in context
- コンビニに行くついでに、切手を買ってきた。(Going to the convenience store, I bought stamps too.) — verb
- 買い物のついでに、郵便局に寄った。(While shopping, I stopped by the post office.) — noun の
- 旅行に行ったついでに、現地の友人に会った。(On my trip, I also met a local friend.) — た-form
- 掃除するついでに、窓も拭いた。(While cleaning, I also wiped the windows.) — verb
- 出張のついでに、実家に帰った。(On a business trip, I also went to my parents'.) — noun の
⚠️ Common mistakes to avoid
① Nouns add 「の」. 買い物のついでに (✗ 買い物ついでに), 散歩のついでに. A noun before ついでに always adds の. Verbs attach directly (dictionary／た-form: 行くついでに).
② 「ついでに」 vs 「ながら」. ついでに = take the chance of A to also do B (two things, main + incidental) (買い物のついでに銀行へ = shopping, also go to the bank); ながら = do two actions simultaneously (multitasking) (音楽を聞きながら勉強 = study while listening to music). ついでに is “do one extra thing while at it,” ながら is “do two at once.”
③ A is main, B is incidental. The point of 「ついでに」 is “since I'm doing A (main) anyway, I'll do B (incidental) too.” So B is usually something “not specially planned, but since it's on the way.”
🔄 Compare with similar forms: ついでに／ながら／がてら
| Form | Nuance | Example |
|---|---|---|
| 〜ついでに | while at it, incidentally (main ＋ incidental) | 買い物のついでに |
| 〜ながら | do two at once (parallel) | 聞きながら書く |
| 〜がてら | while at it (literary, ≈ ついでに) | 散歩がてら |
💡 How to remember this
「ついでに」 is super handy daily — “since I'm doing A anyway, I'll do B too.” 買い物のついでに銀行へ (shopping, also the bank), 出かけるついでにゴミ出して (going out, take the trash too). Attachment: verbs attach directly (行くついでに), nouns add の (買い物のついでに). The easiest confusion is 「ながら」: ついでに = do one extra thing while at it (main + incidental, not necessarily simultaneous); ながら = do two at once (while doing). 「聞きながら書く (write while listening)」 is simultaneous, 「買い物のついでに寄る (stop by while shopping)」 is incidental. To ask someone to do something “while they're at it,” 「〜ついでに」 is most natural.
❓ Quick FAQ
Q: How do I tell 「ついでに」 from 「ながら」?
By “do one extra thing while at it” vs “do two at once.” 「ついでに」 = take the chance of A to also do B (two things, A main, B incidental, not necessarily simultaneous): 買い物のついでに、銀行に寄った (shopping, also stopped by the bank — did the bank on the way). 「ながら」 = do two actions in parallel at the same time (multitasking): 音楽を聞きながら、勉強する (study while listening to music — both at once). Test: “doing A anyway, do B too” = ついでに; “A and B happening at once” = ながら.
Q: How does 「ついでに」 attach? What do nouns need?
Verbs attach directly in the dictionary or た-form: 買い物に行くついでに (going shopping, while at it), 旅行したついでに (having traveled, while at it). Nouns add 「の」: 散歩のついでに (on a walk), 出張のついでに (on a business trip), 買い物のついでに (while shopping). The common mistake is dropping の on nouns (✗ 買い物ついでに). Mnemonic: verb → attach directly, noun → add の. Also 「〜がてら」 (散歩がてら) is a slightly more literary “while at it,” interchangeable.
🖊️ Practice Questions (5)
Q1. 「コンビニに行く___、切手も買ってきて。」(while at the convenience store, also buy stamps)
(A) ついでに (B) ながらに (C) うちに (D) とたんに
Q2. 「旅行___、現地の友人に会った。」(while traveling, also met a local friend) How does it attach to a noun?
(A) のついでに (B) ついでに (C) でついでに (D) についでに
Q3. 「買い物のついでに郵便局に寄った」の意味は?
(A) Took the opportunity of shopping to also stop by the post office
(B) Shopped in order to go to the post office
(C) Shopping and being at the post office at the same time
(D) Neither shopping nor going to the post office
Q4. 「ついでに」と「ながら」の違いとして正しいのは?
(A) ついでに＝take the opportunity to also do (B is secondary); ながら＝doing two actions simultaneously
(B) The two are exactly the same
(C) ついでに＝simultaneously
(D) ながら＝incidentally/while at it
Q5. 接法が正しいのは?
(A) 出かけるついでに買う。 (B) 出かけついでに買う。
(C) 散歩ついでに買う。 (D) 出かけるのついでに買う。
Answer Explanations
1. (A) ついでに ── While at the convenience store, also buy stamps.
2. (A) のついでに ── Noun 「旅行」 ＋ の ＋ ついでに.
3. (A) ── Took the chance while shopping to stop by the post office.
4. (A) ── ついでに = while at it (B secondary); ながら = simultaneously.
5. (A) ── Verb dictionary form ＋ ついでに; a noun needs の, so (C)(D) are wrong.