In order to reduce an assembling man hour of the constituting part for the fuel battery and prevent wrinkles from being generated in an electrolyte membrane, in a constituting part for a fuel battery having electrodes with catalyst in both pole sides of an electrolyte membrane and provided with gas diffusion layers for promoting diffusion of gas in both outer sides thereof, an integrated product between the gas diffusion layers and the gasket, the gas diffusion layers being made of a carbon fiber or the like and impregnated with a rubber, and forming gaskets is bonded to an integrated product of the electrolyte membrane and the electrodes with catalyst by using a hot press.