A variable valve timing apparatus includes a stopper piston which has an equalizing passage in an axial direction. Even if the engaging hole is filled with the oil, the equalizing passage enables the oil flows from an engaging hole to a holding hole when the stopper piston enters into the engaging hole. It is possible to form a vane as narrow as possible, and to enlarge a variable angular range. In addition, the stopper piston has both end faces which are substantially identical in surface area. Even if pulsation arises in oil pressure, pressures acting on both end faces of the stopper piston can be substantially cancelled and position of the stopper piston can be stabilized.