A driving circuit drives a stepping motor in synchronization with an input clock using a 2-phase excitation method. A constant current chopper circuit generates a pulse modulation signal such that the detection value of the coil current approaches a current setting value. A detection window generation circuit generates a detection window. The detection window becomes an open state at a timing at which the coil current IOUT becomes smaller than a predetermined threshold value. A logic circuit sets a full-bridge circuit to a high-impedance state when the detection window is in the open state and controls the full-bridge circuit according to the pulse modulation signal when the detection window is in the closed state. In the open state of the detection window, a back electromotive force (BEMF) detection circuit detects the BEMF of the coil. A current value setting circuit controls a current setting value based on the BEMF.