Causative Form (〜させる): How to Say Make or Let Someone Do
Building the form
Every causative ends in 〜せる or 〜させる, and which one you use is decided purely by the verb group. Turn the plain verb into its stem and attach the right ending:
| Verb type | Rule | Example |
|---|---|---|
| る-verbs | drop る, add させる | 食べる → 食べさせる |
| う-verbs | final u-sound → a-sound, add せる | 書く → 書かせる |
| う-verbs | (more) | 読む → 読ませる, 言う → 言わせる |
| する (irregular) | → させる | する → させる |
| 来る (irregular) | → 来させる | 来る → 来させる (こさせる) |
So the split is simple: させる for る-verbs (and 来る), just せる for う-verbs, with する and 来る memorised as irregulars. Once attached, the whole 〜せる / 〜させる word behaves like an ordinary る-verb, so you conjugate it further as normal — 食べさせない, 食べさせた, 食べさせます.
What the causative lets you say
The formed verb says that one person causes another to do an action. English splits this into two ideas — "make someone do" (force) and "let someone do" (allow) — but Japanese packs both into the same form. Situation, tone, and particles tell you which is meant.
So 子供を行かせる can mean "I make the child go" (an order) or "I let the child go" (permission). The difference lives in the relationship between the people: when the doer wants to act and the causer simply allows it, it reads as "let"; when the doer is being pushed into it, it reads as "make."
先生はヤッタンに漢字を書かせた。
せんせいは ヤッタンに かんじを かかせた。
The teacher made Yattan write kanji.
Coercion sense — the teacher gave the order.
お母さんはヤッタンを公園で遊ばせた。
おかあさんは ヤッタンを こうえんで あそばせた。
Yattan's mom let him play in the park.
Permission sense — same form, allowed rather than forced.
モチはヤッタンの弟に野菜を食べさせた。
モチは ヤッタンの おとうとに やさいを たべさせた。
Mochi made Yattan's little brother eat his vegetables.
The conjugation traps
Three predictable slips catch learners as they build the form.
せる vs. させる. る-verbs (and 来る) take させる; う-verbs take just せる. 食べる → 食べさせる (✓), never 食べせる.
The わ for 〜う verbs. For う-verbs ending in 〜う (like 言う, 買う), the a-sound is わ, not あ — 言わせる, 買わせる, not 言あせる.
を vs. に on the caused person. This is the one to memorise, and it turns on whether the verb already owns a を object:
- Intransitive verbs (no direct object, like 行く, 来る, 帰る): the person made/let to act takes を.
- Transitive verbs (already carry a を object, like 食べる, 読む): the person takes に, because を is "busy" marking the real object.
ヤッタンを行かせる。
ヤッタンを いかせる。
(I) make Yattan go.
行く is intransitive → the person takes を.
ヤッタンに本を読ませる。
ヤッタンに ほんを よませる。
(I) make Yattan read a book.
読む already has its を object (本), so Yattan takes に.
モチは弟にミルクを飲ませた。
モチは おとうとに ミルクを のませた。
Mochi made/let the little brother drink the milk.
飲む is transitive → person takes に.
A clause almost never holds two を, so the moment the verb spends its を on a real object, the caused person shifts to に.
The causative in use
In real sentences the make/let reading falls out of who is causing whom:
部長は社員を残業させた。
ぶちょうは しゃいんを ざんぎょうさせた。
The manager made the employees work overtime.
A boss ordering subordinates → coercion.
ヤッタンが頼んだので、先生は早く帰らせてくれた。
ヤッタンが たのんだので、せんせいは はやく かえらせて くれた。
Because Yattan asked, the teacher let him go home early.
A request granted → permission.
Push the causative into its て-form and add ください and you get one of its most useful everyday shapes — 〜させてください = "please let me…," a polite way to ask permission to do something yourself:
すみません、ここで写真を撮らせてください。
すみません、ここで しゃしんを とらせて ください。
Excuse me, please let me take a photo here.
少し考えさせてください。
すこし かんがえさせて ください。
Please let me think about it for a bit.
You may also meet the causative-passive (使役受身, e.g. 食べさせられる, "to be made to eat"), which combines this form with the passive to say you were forced to do something. That's a separate N4 point worth studying once the plain causative here feels solid.
The short version
- Causative = make or let someone do something; one form, both meanings.
- Form it: る-verbs → drop る + させる; う-verbs → u-sound to a-sound + せる; する→させる, 来る→来させる.
- Intransitive verb → caused person takes を; transitive verb → caused person takes に.
- 〜させてください = "please let me…" (asking permission).
- The causative-passive (〜させられる) is the related "was forced to do" form.
Practice it
Form the causative and pick the right particle (を or に).
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
モチはヤッタンの弟に野菜を＿＿＿。
Frequently asked questions
Does させる mean 'make' or 'let'?
Both. The causative form is identical for coercion ('make someone do') and permission ('let someone do'). Context, tone, and the relationship between the people tell you which. A request like 帰らせてくれた reads as 'let,' while a boss's order reads as 'make.'
When do I use を and when do I use に for the person?
If the verb is intransitive (行く, 来る), the caused person takes を: ヤッタンを行かせる. If the verb is transitive and already has a を object (本を読む), the person takes に instead: ヤッタンに本を読ませる. Japanese avoids two を in one clause.
How do I form the causative of する and 来る?
They're irregular: する → させる, and 来る → 来させる (read こさせる).
What does 〜させてください mean?
It's the て-form of the causative plus ください, used to politely ask permission to do something yourself: 少し休ませてください ('please let me rest a bit').
Where Causative Form fits
Don't confuse it with
- Potential Form · N4 — The potential form means 'can / be able to': 食べる→食べられる, 書く→書ける, する→できる. Learn how to form it by verb group, the が particle shift, and ら-抜き.
- Volitional Form · N4 — The plain volitional form means 'let's ~' or 'I'll ~'. Learn how to make 〜よう/〜おう from every verb type, how it relates to 〜ましょう, and what it builds toward.
Once this clicks, go on to
- 〜てもらう · N5 — 〜てもらう means you receive the favor of someone doing something for you: the receiver is the subject, the doer takes に. Learn formation, the polite ていただく, and how it differs from てくれる and てあげる.
More N4 grammar to explore
Keep going with related patterns at the same level:
- Passive Form — The Japanese passive (受身形): 食べる→食べられる, 書く→書かれる. Learn the formation, the に particle for the doer, and the 'suffering passive' that shows the subject was negatively affected.
- Causative-Passive — The causative-passive 〜させられる says you were made or forced to do something you didn't want to. Learn the formation, the される contraction, and the put-upon nuance.
- 〜ために — 〜ために expresses purpose ('in order to') and benefit ('for the sake of'): dictionary verb + ために, or noun + のために. Learn the formation, the cause use, and how it differs from ように.
- Imperative & Prohibition — The plain imperative (行け, 食べろ, しろ, 来い) gives a blunt command, and dictionary form + な (行くな) forbids one. Learn the formation, the harsh tone, and softer alternatives.
- 〜なさい — 〜なさい gives a firm, polite command: verb ます-stem + なさい (食べなさい, 行きなさい). Used by parents, teachers, and exam instructions. Learn the formation and the casual 〜な.
- Conditional 〜ば — The 〜ば conditional says 'if A, then B' for general truths and natural results: 押せば開く. Learn the verb, い-adjective, and negative forms, plus 〜ば〜ほど.