The hot and cold water mixing valve having a cylindrical casing is provided with a control valve member which adjusts a ratio between hot and cold water inlets by balancing loads applied by a biasing member and an actuator, and cylindrical temperature adjuster which adjusts a position of the control valve member when rotated. In the temperature adjuster, an upper surface is formed at one end, a knob is provided in the center of the upper surface, and a ring-shaped recess is formed around the knob at the upper surface. The temperature adjuster is arranged inside the casing and the knob is inserted, coaxially with the casing, into the hole which opens at one end of the casing. A spacer which covers the recess is interposed and held between the upper surface of the temperature adjuster and one end of the casing.