Patent ID: 8313681

Claim:
A method of manufacturing a seal part in which gaskets are integrally formed on both surfaces of a film-shaped, sheet-shaped or plate-shaped base material, the method comprising the steps of: making a first cavity which is defined between said base material and a first split mold contacting to one side of said base material and to which a molding material-supplying gate is open, and a second cavity which is defined between said base material and a second split mold contacting to the other side of said base material, to communicate with each other via a first communicating hole which is provided in said base material; and providing, in said first split mold, a first air vent hole which is open to a confluent portion of a molding material in said first cavity, and a second air vent hole which is positioned at and open to a second communicating hole provided in said base material at a confluent portion of the molding material in said second cavity so as to be away from the surface of said base material.