Meaning & Usage
✨ Basic Meaning
“At once,” “all at the same time,” “in a single instance,” or “in one go.”
🎯 Primary Function
An adverbial phrase used to emphasize that an action or process is completed in a single, concentrated effort, or that multiple things happen simultaneously or in one batch.
📋 Grammar Structure
一度に + [Verb]
N/A (Once an adverb, it modifies verbs, not i-adjectives.)
N/A (Once an adverb, it modifies verbs, not na-adjectives.)
一度に + [Verb Negative Form] (e.g., 一度にできない)
🎭 Usage Contexts
Formal Situations
Appropriate in business or academic reports when describing efficient processes or simultaneous events.
Informal Situations
Very frequently used in daily conversation for tasks, consumption, or actions.
Written Language
Common in instructions, descriptions, and literature.
Spoken Language
High frequency, essential for describing efficiency and simultaneous actions.
💡 Common Applications
Handling large quantity or volume.
Used to emphasize that a large batch or complete set of items was managed or processed in a single, unified action.
Example: 全部の書類を一度にコピーした。
Simultaneous or concentrated action.
Indicates that multiple events, tasks, or actions are happening within the same, singular time frame or attempt.
Example: 二つの会議に一度に出席することは不可能だ。
Reference to rapid or sudden change.
Describes an event or change that occurred rapidly and suddenly, emphasizing the quickness and singularity of the deterioration or shift.
Example: 彼の病状は一度に悪化した。
Frequency
High. Extremely common in both written and spoken Japanese.
Difficulty
N3-N2 (Essential vocabulary/adverbial usage)
Tag:
Example Sentences
Example #1
この資料を一度に印刷してください。
Furigana: このしりょうをいちどにいんさつしてください。
Romaji: Kono shiryō o ichido ni insatsu shite kudasai.
English: Please print all of these documents at once.
Example #2
漢字を一度にたくさん覚えるのは難しい。
Furigana: かんじをいちどにたくさんおぼえるのはむずかしい。
Romaji: Kanji o ichido ni takusan oboeru no wa muzukashii.
English: It is difficult to memorize many kanji at once.
Example #3
そんなにたくさんの荷物を一度に持てますか。
Furigana: そんなにたくさんのにもつをいちどにもてますか。
Romaji: Sonnani takusan no nimotsu o ichido ni motemasu ka.
English: Can you carry that much luggage at once?
Example #4
彼女は電話をしながら、メールも一度にチェックしている。
Furigana: かのじょはでんわをしながら、メールもいちどにチェックしている。
Romaji: Kanojo wa denwa o shinagara, mēru mo ichido ni chekku shite iru.
English: She is checking her email simultaneously while talking on the phone.
Example #5
一度に全てを解決することはできない。
Furigana: いちどにすべてをかいけつすることはできない。
Romaji: Ichido ni subete o kaiketsu suru koto wa dekinai.
English: It is not possible to solve everything at once.
Example #6
全ての情報が一度に入ってきたので、混乱した。
Furigana: すべてのじょうほうがにいちどにはいってきたので、こんらんした。
Romaji: Subete no jōhō ga ichido ni haitte kita node, konran shita.
English: All the information came in at once, so I got confused.
Example #7
引っ越しは大変なので、全てを一度にやろうとしない方がいい。
Furigana: ひっこしはたいへんなので、すべてをいちどにやろうとしないほうがいい。
Romaji: Hikkoshi wa taihen na node, subete o ichido ni yarou to shinai hō ga ī.
English: Moving is tough, so it’s better not to try to do everything in one go.
Example #8
薬は一日三回、一度に一錠飲んでください。
Furigana: くすりはいいちにちさんかい、いちどにいっじょうのんでください。
Romaji: Kusuri wa ichinichi sankai, ichido ni ichijō nonde kudasai.
English: Take the medicine three times a day, one tablet at a time.
Example #9
彼の成功は一度に訪れたわけではない。
Furigana: かれのせいこうはいちどにおとずれたわけではない。
Romaji: Kare no seikō wa ichido ni otozureta wake de wa nai.
English: His success did not happen all at once. (It was gradual.)
Example #10
効率を考えると、まとめて一度に処理する方がいい。
Furigana: こうりつをかんがえると、まとめていちどにしょりするほうがいい。
Romaji: Kōritsu o kangaeru to, matomete ichido ni shori suru hō ga ī.
English: Considering efficiency, it’s better to gather them up and process them all at once.
Notes & Nuances
📌 Important Points
Emphasizes Singularity of Action/Batch.
While often translated as “at once,” 一度に strongly implies dealing with a batch or quantity in a single, singular effort, emphasizing the *completeness* of the action in one instance.
Example: この部屋の掃除は、一度で終わらせよう。
Implies Efficiency and Concentration.
It can mean truly simultaneous actions, but more often implies actions done within a continuous, single stretch of time without interruption or division.
Example: 彼はメールの返信と電話を一度に行った。
Commonly paired with Volume-Handling Verbs.
Because of its meaning, 一度に is very frequently used with verbs related to handling volume (e.g., 処理する, 覚える, 運ぶ, 食べる) and often appears in negative sentences to express impossibility.
Example: 全部の質問に一度に答えるのは大変です。
⚠️ Common Mistakes
❌ 一度に図書館に行ったことがある。
✅ 全てを一度にやろうとしないで、一つずつやりなさい。
When referring to the *count* of actions (e.g., “I went there once”), use 一回 (ikkai). 一度に refers to the *manner* of the action (all at the same time).
❌ 一度の全部の料理を食べきるのは無理だ。
✅ 一度に全部の料理を食べきるのは無理だ。
Do not use the particle の (no) after 一度に; it acts as an adverb and directly modifies the verb.
❌ 一度に運んだ。 (Ambiguous what was transported in one batch.)
✅ 会議は同時に二つ開催された。 (or 二つの会議が同時に開催された)
While both are similar, 一度に often requires the use of the object particle を to clearly delineate the batch being acted upon (e.g., 荷物を一度に運ぶ). Omitting this can sometimes sound awkward.
🏛️ Cultural Context
Politeness Level: Neutral. The level of politeness is determined by the verb form (e.g., ます form for polite).
Social Situations: Used widely, particularly when discussing efficiency, workload, or multitasking.
Regional Variations: Standard across all regions.
🔍 Subtle Differences
同時に (dōji ni)
同時に focuses purely on *strict temporal coincidence* (happening at the exact same moment). 一度に focuses on *completing a batch or task in a singular, non-divided effort*.
When to use: Use 同時に when two independent events happen at the same clock time (e.g., The announcement was made, and the stock price changed *simultaneously*). Use 一度に when one action covers multiple targets in one go (e.g., I bought all three books *at once*).
一斉に (issei ni)
一斉に means “all at once” but specifically emphasizes many individuals or items acting in unison or concert (e.g., The crowd cheered *all at once*). 一度に applies to an object or task handled by a single entity (person or machine).
When to use: Use 一斉に for group actions. Use 一度に for single actions dealing with multiple objects or aspects.
📝 Conjugation Notes
一度に is an adverbial phrase formed by a noun (一度) and a particle (に) and does not conjugate. It modifies the verb that follows it.
🔊 Pronunciation Tips
The pitch accent is usually flat (low-low-low-low). The に (ni) is pronounced clearly, linking the adverb to the verb.
🧠 Memory Tips
Break it down: 一 (ichi = one) + 度 (do = time/occurrence) + に (ni = at). “At one time/at one occurrence.” Visualise juggling multiple balls and catching them all in a single grab.
Other Grammar
I’m a software engineer based in Japan, with experience in developing web and mobile applications. I’m passionate about technology, especially in DevOps, AI, and app development using platforms like AWS, Flutter, and Node.js. My goal is to build a website that shares knowledge about the Japanese language and IT, helping everyone learn and grow more easily in the digital era.