A membrane-electrode assembly including a polymer electrolyte membrane, and electrocatalyst layers disposed on both surfaces of the polymer electrolyte membrane, with a total light transmittance measured after delamination of both the electrocatalyst layers by using an adhesive member is 40% or less. The total light transmittance is at an electrocatalyst layer located part, when a total light transmittance at an electrocatalyst layer non-located part is taken to be 100%. The viscous member has an adhesive force of 3 N/10 mm or more when measured by pulling the viscous member adhered to a stainless steel in a 180°angle direction relative to the stainless steel, for delamination from the stainless steel.