Improvement in the yield of a semiconductor device is aimed at. When extruding a molded body with the ejector pin which performs advance-or-retreat movement at the projecting portion which projects from this bottom face in the bottom face of a mold cavity corresponding to the surface and the mounting side of a molded body after forming a molded body, depressed portions being formed in the surface and the mounting side by projecting portions, they can extrude. When accumulating molded bodies themselves in the baking step after a resin molding step and performing bake, by arranging the resin burr which furthermore withdrew from the surface and the mounting side in the depressed portion, bake can be performed in the condition that the accumulated molded bodies are stuck. Therefore, the form of deformation of a warp etc. of each molded body or a lead frame, can be made uniform, and, as a result, improvement in the yield of QFP (semiconductor device) is aimed at.