The fuel cell comprises: a membrane electrode assembly having a solid polymer electrolyte membrane, an anode side diffusion electrode (an anode electrode, and a second diffusion layer) disposed at one side of the solid polymer electrolyte membrane, and a cathode side diffusion electrode (a cathode electrode, and a first diffusion layer) disposed at the other side of the solid polymer electrolyte membrane; a pair of separators which hold the membrane electrode assembly; a projecting portion which extends from the solid polymer electrolyte membrane and which projects from the peripheries of the anode side diffusion electrode and the cathode side diffusion electrode; and a seal, provided on the separators, which was liquid sealant at the time of application. The seal makes contact with the projecting portion while the membrane electrode assembly is disposed between the separators.