PURPOSE: To enable reduction of the number of parts by fitting a vane actuating body provided with an elastic projection piece to the lateral surface part of a rotor, pressing the vane on the inner-peripheral surface of a cam ring and thereby unnecessitating a spring for energization.

CONSTITUTION: The vane actuating body 23 consists of the main body 24 of a ring and the elastic projection piece 25 formed by bending. This vane actuating body 23 is housed in a concave part 22 under the condition that the elastic projection pieces 25 are made to contact elastically with the base end part 10 of each vane 2. Under the condition, the vane actuating body 23 is held in a state concentrical to the round inner-peripheral surface 4 of the cam ring 5 and the tip part 11 of each vane 2, while going in and out from the groove part 1 of the rotor 3, is kept at a state contacting with the inner-peripheral surface of the cam ring 5. Therefore, it becomes unnecessary to fit a spring for energizing with respect to each vane and thereby the number of parts can be reduced.