A capacitive touch panel can select a way of voltage control with a high degree of detection accuracy according to operating environment. In response to approach of an input unit, the stray capacitance of the sensing electrode the input unit approached increases. Accordingly, charge and discharge of the stray capacitances of a plurality of sensing electrodes are controlled, and a sensing electrode the potential change of which is made slow by the increase in stray capacitance and resultant increase in time constant is detected as a sensing electrode the input unit approached. The stray capacitance of a sensing electrode can selectively be controlled either by the charge control or by the discharge control, and optimum one of the controls is selected according to operating environment.