An object of the present invention is to provide, in the manufacture of a membrane-catalyst assembly including a polymer electrolyte membrane and a catalyst layer bonded to the polymer electrolyte membrane, a method that achieves both the relaxation of thermocompression bonding conditions and the improvement of adhesion between the catalyst layer and the electrolyte membrane with high productivity. A main object of the present invention is to provide a method of manufacturing a membrane-catalyst assembly including an electrolyte membrane and a catalyst layer bonded to the electrolyte membrane, the method including a liquid application step of applying a liquid to a surface of the catalyst layer before bonding, and a thermocompression bonding step of bonding, to the electrolyte membrane, the catalyst layer to which the liquid is applied by thermocompression bonding.