PURPOSE: To form into a complicated shape by a later machining in an insert mold body wherein a metallic insert member is embedded in an EPDM made rubber base body by bonding the insert member to the rubber base body via a laminated film composed of a specific material.

CONSTITUTION: In an insert mold body provided with an EPDM made rubber base body 5 and a metallic insert member 3 embedded in this rubber base body 5, the insert member 3 is thermally welded in the rubber base body 5 via a laminated film 7A. The laminated film 7A is constituted of a first film 11A arranged on the side of the rubber base body 5 and a second film 13A arranged on the side of the insert member 3. For a material of the first film 11A an olefin resin having a polar functional group is adapted while for a material of the second film 13A a thermoplastic resin having a polarity, for example, a copolymerized polyester resin is adapted.