A hydrogen generating apparatus including a reformer which performs a reforming reaction using a material and steam to generate hydrogen-containing gas; a water evaporator which generates the steam supplied to the reformer; a first water pathway through which reforming water to be supplied to the water evaporator flows; a pump which supplies the reforming water to the water evaporator 1a; a second water pathway 7 branching from the first water pathway on the downstream side of the pump; a first water tank to which the water flowing through the second water pathway flows; a first flow rate controller provided on the second water pathway; and a controller which operates the pump and controls the first flow rate controller so that water flows through the second water pathway, thereby stably generating hydrogen and preventing degradation of the reformer thereof is realized.