[OBJECT] A hydrogen generator is provided which includes a lightweight, small-heat-capacity, high-performance gas mixer and is good in hydrogen generating efficiency and response.[MEANS OF SOLVING] A hydrogen generator comprising: a mixed gas passage (9) configured to flow a mixed gas containing two or more components; first and second passages configured to branch off, at their leading ends, from the mixed gas passage and join to each other at their trailing ends; first turning means (45a) to (45d) formed in the first passage to turn the mixed gas flowing in the first passage in a first direction; second turning means (46a) to (46d) formed in the second passage to turn the mixed gas flowing in the second passage in a second direction opposite to the first direction; and a hydrogen generating section configured to generate hydrogen by causing a chemical reaction of the mixed gas which flows out from the joined trailing ends of the first and second passages.