To solve the problem wherein there are a large number of parts to mount on a cylindrical end part of a cap pressing a diaphragm occluding an opening of a cylindrical end part of a housing and the work for mounting is troublesome, in a hot water flow regulating valve.

A hot water flow regulating valve 35 consists of a housing 40 having a first flow inlet port 56 and a first flow outlet port 58, a flow passage 54, a valve seat 59, and an opened cylindrical lower end part 91, a shaft member 70 having a valve part 74 opposing to the valve seat and changing the distance between a valve part and the valve seat by movement, the diaphragm 112 liquid-tightly sealing the flow passage, and the cap 100 having a cylindrical insertion part 103 pressing the diaphragm. Guide parts 93, 106 and welded parts 92, 104 are formed between an inner surface of the cylindrical end part 91 and an outer surface of the cylindrical insertion part 103.