PURPOSE: To provide a ternary output circuit capable of preventing reduction of the degree of integration by back gate control circuit.

CONSTITUTION: An output signal COM at a Vcc level is output from an output terminal To by turning on a transistor Tr11 whose source is connected to a Vcc and whose drain is connected to the output terminal To. An output signal COM of a Vss level is output from the output terminal To by turning on a transistor Tr12 whose drain is connected to the output terminal To and whose source is connected to a Vss. An output signal COM of a -Vcc level is outputted from the output terminal To by turning on a transistor Tr13 whose drain is connected to the output terminal To and whose source is connected to a -Vcc whose voltage is lower than the Vss level. The back gates of the transistors Tr12 and Tr13 are connected to the -Vcc.