A position detecting device includes: X-axis electrodes and Y-axis electrodes; a driving section for supplying an AC signal to the X-axis electrodes; a synchronous clock generating section for generating synchronous clock signals at the timing when the AC signal passes through zero-cross points; a first switch for selectively supplying the AC signal outputted from the driving section to one of the X-axis electrodes at the timing of the synchronous clock signal; a second switch for selecting one of the Y-axis electrodes at the timing of the synchronous clock signal; a synchronous detector for synchronous-detecting a signal outputted by the Y-axis electrodes through the second switch; and a position calculating section for calculating a position indicated by an indicator based on the signal outputted from the synchronous detector, wherein the position corresponds to one or more intersections of the X-axis electrodes and Y-axis electrodes.