A hydrogen supplying apparatus equipped with a hydrogen separation membrane and a catalyst plate, which is made by forming a catalyst layer on a metal plate, wherein the metal material of the membrane is different in hardness from that of the catalyst plate.A method of producing the hydrogen supplying apparatus, which comprises: bonding a catalyst plate and a hydrogen separation membrane to each other, by friction-stir welding, wherein a welding tool is pressed towards only one of the membrane and catalyst plate, forming a reaction layer between the membrane and the catalyst plate by the frictional heat, and forming ripples in the welded interface.