Even if an internal combustion engine is stopped having a lock pin of a vane rotor kept disengaged from a lock recess, subsequent engine starting can instantly move the vane rotor to a desired angular position where the lock member an be engaged with the lock recess. The vane rotor has therein two passage control mechanisms each having a hydraulically actuated valve body. When the valve body is moved to a given position, retarding and advancing hydraulic holes become communicated to each other through an annular groove of the valve body. Due to this ON communication, retarding and advancing operation chambers become communicated, so that reciprocative swing movement of the vane rotor induced by an alternating torque produced at the starting of the engine is effectively made and thus the vane rotor can be quickly turned to the desired angular position for ease of engine starting.