The present invention discloses a membrane for a fuel cell, comprising: a solid polymer electrolyte membrane composed of a crosslinked ion exchange resin, and a polymer having a weight-average molecular weight of 5,000 to 1,000,000 and having a charge group of polarity opposite to that of the ion exchange group of the ion exchange resin, which polymer is adhered onto at least one surface of the solid polymer electrolyte membrane in an amount of 0.0001 to 0.5 mg/cm3, preferably in a state that, when the membrane for fuel cell is immersed in a 50 mass % aqueous methanol solution of 30° C., there is substantially no difference in the adhesion amount of the polymer before and after the immersion; and a membrane-electrode assembly for a fuel cell, comprising the above-mentioned membrane, and a catalyst electrode layer bonded to the membrane, which catalyst electrode layer contains an ion exchange resin having the same polarity as the crosslinked ion exchange resin composing the solid polymer electrolyte membrane, and a catalyst substance.