To reduce the number of part items, simplify structure and improve assemblage by making a body part of a bimetal valve of hard synthetic resin, and forming a valve seat part, constituting a part of the body part, of a thermoplastic elastic body softer than synthetic resin of the body part and different in quality.

A bimetal valve 1 for opening/closing an air passage using warping of bimetal 2 caused by temperature change in an intake system or the like of an internal combustion engine for an automobile consists of a body part 3 made of hard synthetic resin, and the bimetal 2. An orifice part 8 with a valve seat part 4, and an air passage 9 are formed at one end of the body part 3, and a bimetal fixing part 6 and an adjusting screw part 7 are formed at the other end part. The tip part of the valve seat part 4 is formed of a soft thermoplastic elastic body formed integrally with the hard synthetic resin of the body part 3 by heat fusion. This bimetal valve 1 can omit the use of a conventional valve fitted to the tip of the bimetal 2 so as to be able to reduce the number of part items and cost.