〜ことになると
Formation
Meaning
An expression used when a person's attitude or emotional state suddenly changes when talking about a certain topic. Usually followed by a clause describing a change in behavior or mindset.
Note
Used to describe a situation where someone's behavior, expression, or attitude changes significantly when they encounter a specific topic or field they are passionate about or sensitive to. It is often translated as 'When it comes to...' or 'Once the topic turns to...'. The structure '〜こととなると' is a more emphatic and slightly more formal variant.
Examples
彼は仕事のことになると、急に顔つきが変わる。
When it comes to work, his facial expression suddenly changes.
彼女は料理を作ることになると、人が変わったように熱心になる。
When it comes to cooking, she becomes as enthusiastic as if she were a different person.
あいつはテニスのこととなると、時間を忘れて話し続ける。
When it comes to tennis, he keeps talking and forgets about the time.
ギャンブルのことになると、彼は冷静さを失ってしまう。
When it comes to gambling, he loses his cool.
食べ物のことになると、彼女の目は輝き始める。
When it comes to food, her eyes start to sparkle.
音楽のこととなると、彼は一歩も譲らない。
When it comes to music, he won't give an inch.