To provide a method capable of producing, by means of mechanical pulverization, a resin powder having a high bulk density and an average particle size of at most 50 μm from resin particles containing a fluorocopolymer as the main component and having a melting point of from 260 to 320° C., such as PFA. The method is to obtain a resin powder having an average particle size of from 0.02 to 50 μm by subjecting resin particles (A) having an average particle size of at least 100 μm to mechanical pulverization treatment. The resin particles (A) is made of a material (X) having a fluorocopolymer (X1) as the main component; and said fluorocopolymer (X1) has a unit (1) based on a monomer containing at least one type of functional group selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group and an isocyanate group, and a unit (2) based on tetrafluoroethylene, and has a melting point of from 260 to 320° C.