Method for manufacturing composite molded member, and composite molded member

The purpose of the present invention is to further improve sealing performance by ribs. In a method for manufacturing a composite molded member provided with an inner member, a primary molded part covering the inner member, and a secondary molded part covering the primary molded part, a rib part protruding toward the secondary molded part side is formed in the primary molded part, the method for manufacturing the composite molded part comprises the following steps: (a) arranging an intermediate part including the inner part and the primary molded part in a mold; (b) allowing the resin for the secondary molding part to flow into the mold; (c) detecting the temperature of the resin for the secondary molding part in the mold; (d) determining, on the basis of the resin temperature, a meltable time during which the resin for the secondary molded part in the mold can melt the rib part of the primary molded part; (e) determining whether the molten state of the rib is good based on the meltable time; (f) removing the