A hydrogen generating device including a temperature adjustment section 8 for controlling a temperature of a hydrogen-containing gas to be introduced from a reforming section 1 into carbon monoxide reducing sections 2 and 3, the temperature adjustment section 8 including: a heat exchange section 26 having an air path 11 for allowing a cooling air to pass therethrough; an air intake portion 10 having an opening for taking the cooling air into the air path 11; and an air discharging portion 12 having an opening for discharging the cooling air out of the air path 11, wherein the opening of the air intake portion 10 and that of the air discharging portion 12 are facing in a same direction, and the same direction is a vertically upward direction or a vertically downward direction.