A touch detection circuit has a first terminal and a second terminal which are respectively coupled to a first electrode and a second electrode located adjacent to each other. The capacitance sensing circuit (i) senses first electrostatic capacitance formed by the first electrode in a space with a periphery including the second electrode, and (ii) senses, by a self-capacitance method, second electrostatic capacitance formed by the first electrode in a space with a periphery in a state where voltage of the second terminal is made to follow voltage of the first terminal. A signal processor detects water over the first electrode and the second electrode on the basis of a difference between the first electrostatic capacitance and the second electrostatic capacitance.