How to tell them apart
The core contrast is that 恐れがある conveys a genuine concern about an undesirable outcome, typically used in formal or public contexts like product warnings or safety announcements, while かもしれない simply states uncertainty without any negative connotation. Swapping them feels unnatural: saying 携帯電話が発熱するかもしれない sounds too casual for a company announcement, while 忘れた恐れがある overstates a mundane possibility as a serious risk. 恐れがある is almost always tied to bad outcomes, whereas かもしれない is neutral and works for any possibility, good or bad.
- 恐れがある Use 恐れがある when expressing concern about a negative or risky outcome, especially in formal or public contexts.
- かもしれない Use かもしれない when simply stating that something might be true, with no implication of risk or concern.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| 恐れがある regaaru | there is a danger/risk that | N2 |
| かもしれない kamoshirenai | might; possibly; perhaps | N4 |
恐れがある regaaru
there is a danger/risk that
恐れがある expresses that there is an objective risk that something bad may happen, often used in warnings, news reports and formal announcements. It follows the plain non-past form of a verb, as in 割れる恐れがある, or a noun with の, as in 洪水の恐れがある. It does not describe a personal feeling of fear, and it is used only for undesirable outcomes, not for neutral or positive events.
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そういう事故は再発するおそれがある。
Such an accident is likely to happen again.
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私たちは命を失うおそれがあった。
We were in danger of losing our lives.
かもしれない kamoshirenai
might; possibly; perhaps
かもしれない expresses uncertain possibility, like might or perhaps, when the speaker is not sure if something is true or will happen. It follows the plain form of verbs and i-adjectives, as in 行くかもしれない or 高いかもしれない, and follows nouns and na-adjectives directly, as in 病気かもしれない or 静かかもしれない. For past possibility, use だったかもしれない, as in 病気だったかもしれない. It sounds conversational and uncertain, so avoid it for stating facts with confidence.
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金持ちかもしれないがけちだ。
He may be rich, but he is stingy.
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オーストラリアに行かなきゃいけないかもしれないんだ。
I may have to go to Australia.
恐れがある and かもしれない are JLPT N4–N2 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.