Process for producing a coating film and process for producing a solid polymer electrolyte fuel cell

A process for producing a coating film consisting of a single coating layer or a plurality of coating layers laminated, which comprises a coating operation of relatively moving at least one of a die for discharging a coating liquid containing short fibrous fillers from a linear opening with a predetermined length and a substrate for coating, on which the coating liquid discharged from the die is coated, to form a coating layer on the substrate for coating, wherein the direction in the coating operation includes at least two different angle directions with regard to the single coating layer or the plurality of coating layers of the coating film.