To enable a plunger to follow the sharp advance of the vane body caused by reaction force of torque from an engine valve as well as to improve control response and level of quietness.

A tip of plunger 14 is abutted by pressing to a separation wall portion 13 of a housing 2 via a shoe 67, by mounting the plunger 14 slidably to a vane body 4 connected to a cam shaft and introducing pressure in an advance angle side hydraulic chamber 27 into a pressure chamber 47 in the plunger 14 when advance angle side rotation is controlled. The tip of the shoe 14 is made to always contact the separation wall portion 13 in a plane by mounting the shoe 67 at the tip of the plunger so that the neck of the shoe is swingable. When the plane contact portion of the shoe 67 is trying to separate from the separation wall portion 13, the separation is inhibited by pressure decrease in the surrounding area and viscosity of the operation oil. Therefore, the plunger 14 is made to reliably work following the rotation of the vane body 4.