A switch circuit which can operate with a single low voltage is provided. A plurality of (i=0 to n) series circuits of a capacitor (Ci) and a path of the drain-source of a MOS-FET (Qi) are connected in parallel to each other between a first terminal T1 and a second terminal T0. In each of the series circuits, a pull-up resistor Ri is connected between an output terminal of an inverter Ai and a junction between the capacitor Ci and the MOS-FET (Qi). Each bit bi of digital data for controlling the capacitance is supplied to the gate of the MOS-FET (Qi) and the inverter Ai in each of the series circuits. Capacitance which varies in response to the value of the digital data is obtained between the first terminal T1 and the second terminal T0.