A variable valve timing apparatus including: an actuator housing having a space at the inside thereof; an upper plunger mounted inside the upper portion of the actuator housing to move upward and downward; a lower plunger mounted inside the lower portion of the actuator housing to allow the upper plunger to move upward and downward; an oil chamber allows oil to be circulated upwardly and downwardly or blocks the flow of oil through a head formed on the top end periphery of the upper plunger in accordance with the upward and downward movements of the upper plunger; and a communicating passage allows the upper and lower end portions of the oil chamber to communicate with each other in accordance with upward and downward movements of the lower plunger and to adjust the oil flowing thereon to control the speeds of the upward and downward movements of the upper plunger.