A manufacturing method of a cartridge that is detachably mountable to an apparatus main assembly of an image forming apparatus. The manufacturing method includes a step of integrally molding a cartridge electrode with a frame in a manner such that a mold is contacted to the frame to form a space including a first portion for forming a first contact portion, a second portion for forming a second contact portion, and a connecting portion branching from an injection portion into the first portion and the second portion, and electroconductive resin is injected into the space.