An electrostatic sensor detecting a position of an object being approaching the electrostatic sensor includes a first electrode group including electrodes, a second electrode group including electrodes adjacent to the electrodes of the first electrode group, detection circuits connected to electrodes selected from among the electrodes of the first and second electrode groups and having first alternating-current sources and current measurement units, a second alternating-current source connected to unselected electrodes among the electrodes of the first and second electrode groups, and a controller. The controller successively selects electrodes to be connected to the detection circuits from among the electrodes of the first and second electrode groups, causes the selected electrodes to be connected to the detection circuits, and detects a position of the object based on current detected by the current measurement units.