VALVE TIMING ADJUSTMENT DEVICE

Hall sensors respectively output a measurement signal, a voltage level of which changes according to a rotation position of an electric motor. A rotation signal generator of a drive circuit generates a rotation speed signal and a rotation direction signal of the electric motor based on the measurement signals. A control circuit generates control signals of the electric motor according to edges of output signals of the rotation signal generator. A signal corrector corrects an excess or a shortage of the edge of the signal at the time of starting the electric motor based on: the voltage levels of the rotation speed signal and the rotation direction signal at the time of turning off and the time of turning on of an electric power source; and a rotation direction of the electric motor at the time of starting thereof.