A position detecting device is provided. The position detecting device includes a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, and a tablet which detects a position pointed to by the position pointer when receiving the position-pointing signal. The position pointer includes a coil, a charging circuit for charging the power storage unit, and a transmitter for transmitting the position-pointing signal. The tablet includes an excitation coil wound around a periphery of a position detecting area of the tablet, an excitation circuit for supplying an alternating voltage to the excitation coil, a position-pointing signal detector for detecting the position-pointing signal received from the position pointer, and an excitation controller for controlling a supply of the alternating voltage to the excitation coil based on the detected position-pointing signal.