To converge to a target rotation phase without causing a response delay and overshoot even if there are dispersions in hysteresis characteristics in a variable valve timing device controlling the rotation delay of a cam shaft relative to a crankshaft by frictional braking by an electromagnetic brake.

This variable valve timing device determines the control direction in approaching to the target rotation phase, and when converged to the target rotation phase by a delay control, gradually increases the hysteresis quantity. This device learns the hysteresis quantity in a phase advance side based on the hysteresis quantity when the rotation phase starts to make phase advance, then gradually reduces the hystereisis quantity, and learns the hysteresis quantity in the side of the phase lag based on the hysteresis quantity when the rotation phase starts to make phase lag.