A buffer circuit includes a first transistor circuit having a first conductivity type transistor, a second transistor circuit having a second conductivity type transistors, in which the first and second transistor circuits are serially connected between a first fixed power supply and a second fixed power supply, and input terminals and output terminals of each of the first and second transistor circuits are connected in common respectively, in which at least one transistor circuit of the first transistor circuit and the second transistor circuit is a double gate transistor, and in which wherein a switch element, when any one transistor circuit of the first and the second transistor circuits is in an operating state, is included to supply a voltage of a third fixed power supply to a common connection node of the double gate transistor of the other transistor circuit.