A noise removing circuit includes a capacitor, a buffer circuit, and a switch. The capacitor includes a first terminal and a second terminal. The buffer circuit includes a third terminal and a fourth terminal. The switch sets the capacitor and the buffer circuit to be in one of a first state and a second state. In the first state, the first terminal is connected to the fourth terminal, a reference voltage is input to the second terminal, and the third terminal is connected to the signal source. In the second state, the first terminal is connected to the signal source, and the second terminal is connected to the third terminal.