A variable valve timing controller according to the present invention comprises a locking mechanism for holding the vane in the middle of the pressure chamber until the internal combustion engine starts; and a damper for sealing up one of the advance chamber and the delay chamber and for slowing the relative rotation between the rotational shaft and the rotation-transmitting member. According to the present invention, the locking mechanism maintains the vane in the middle of the pressure chamber until the internal combustion engine starts. Therefore, the vane cannot vibrate even when unstable transitional pressure is supplied to the pressure chamber so that no undesirable noise shall be generated. Further, the valve timing may be further delayed after the internal combustion engine starts since the vane is maintained in the middle of the pressure chamber. Therefore, the valve timing may be consistently optimized not only for easy engine starting but also for the high-speed operation of the internal combustion engine. Thus, the volumetric efficiency can be improved by the inertia of the air intake under high-speed operation of the internal combustion engine.