Abstract: A laminating apparatus for laminating an object to be laminated includes an upper chamber and a lower chamber which are partitioned by a diaphragm, a heater board provided in the lower chamber, and a diaphragm capable of freely expanding for pressurizing the object to be laminated mounted on the heater board, in which the diaphragm is constituted of butyl rubber. The composition of the butyl rubber includes, for example, 100 to 0 parts by weight of halogenated butyl, 0 to 100 parts by weight of regular butyl, 1 to 5 parts by weight of magnesium oxide, 5 to 100 parts by weight of carbon black, 0 to 20 parts by weight of paraffin oil, 1 to 5 parts by weight of zinc oxide, 1 to 20 parts by weight of resin vulcanizing agent, and 0 to 10 parts by weight of processing aid. According to the present invention, the lifetime of the diaphragm is extended, and laminated objects can be produced at a low cost.