Disclosed is a hydrogen generator that prevents the reformate water from bypassing the evaporator in a hydrogen generator, and the occurrence of sudden temperature changes within an evaporation flow path. The hydrogen generator comprises: an evaporator that produces a mixed gas by mixing a raw material gas containing methane with water vapor; a reformer that changes the mixed gas into a hydrogen-containing gas through a steam reforming reaction; and a combustor that supplies heat to the evaporator and the reformer. The evaporator comprises: an inner cylinder; an outer cylinder enclosing the inner cylinder; and a middle cylinder that is inserted between the inner cylinder and the outer cylinder, and that defines a helical flow path between the inner cylinder and the outer cylinder, through which water supplied from the outside flows.