A valve timing controller includes a driving circuit, a control circuit, and a signal line. The driving circuit controls electricity applied to the electric motor according to a control signal, and generates a rotation-direction signal which indicates a rotation direction of the electric motor by a voltage level. The control circuit outputs the control signal which is generated according to the rotation-direction signal. The rotation-direction signal is transmitted from the driving circuit to the control circuit through the signal line. The driving circuit outputs the rotation-direction signal of high-level during a predetermined period after the control signal is outputted.