A hydrogen generator of the present invention includes a reformer (16) for generating a hydrogen-containing gas through a reforming reaction using a raw material; a combustor (102a) for heating the reformer (16); a combustion air supplier (117) for supplying combustion air to the combustor (102a); and an abnormality detector (110a) for detecting an abnormality; and a controller (110) configured to control the combustion air supplier (117) such that the reformer (16) is cooled with a higher rate in an abnormal shut-down process executed after the abnormality detector (110a) detects the abnormality, than in a normal shut-down process.