Resin molding method

A resin molding method comprising:

• a first molding step of molding a first molded part and a second molded part in different positions in a mold by injecting resin into the mold;
• and
• a second molding step of joining the first molded part and the second molded part to form a resin molded article by engaging the first molded part and the second molded part in a first direction inside the mold and injecting resin into engaged portions,
• wherein in the first molding step, the second molded part is formed by injecting resin into an area where a first core movable in the first direction and a second core movable in a second direction intersecting with the first direction are engaged,
• wherein the first core comprises protrusions in the first direction,
• wherein in the second molding step, the second molded part is joined to the first molded part by injecting the resin while the first core is in contact with the second molded part and the second core is removed from the second molded part,
• wherein areas where the first core and the second core are located in the first molding step become hollow areas connected to each other by removing the first core and the second core from the second molded part, and
• wherein in the engagement in the first molding step, at least one of the protrusions of the first core in the first direction is not in contact with the second core in the first direction.