[Problem] To improve durability of a hot and cold water mixing valve.[Means to Solve the Problem] The hot and cold water mixing valve having a cylindrical casing 1 is provided with a control valve member 2 which adjusts an opening/closing ratio between a hot water inlet a and a cold water inlet b, by balancing between loads applied by a biasing member 4 and an actuator 5, and cylindrical temperature adjusting means 8 and 9 which adjusts a position of the control valve member 2 when subjected to rotation by a user. In the temperature adjusting means 8 and 9, an upper surface 81 is formed at one end, a knob 82 is provided in the center of the upper surface 81, and a ring-shaped recess 83 is formed around the knob 82 at the upper surface 81. The temperature adjusting means 8 and 9 are arranged inside the casing 1 such that the knob 83 is inserted, coaxially with the casing 1, into the hole 12 which opens at one end of the casing 1. A spacer 100 which covers the recess 83 formed at the upper surface 81 is interposed and held between the upper surface 81 of the temperature adjusting means and one end of the casing 1.