Two terminals of each of transistors (P1, N1) are connected between two terminals (A, B). A body effect compensation circuit (COMP-P1) for the transistor (P1) and a body effect compensation circuit (COMP-N1) for the transistor (N1) are arranged. The back gates of transistors (P1P, P2P) in the circuit (COMP-P1) and transistors (P1N, P2N) in the circuit (COMP-N1) are commonly connected to the back gate of the transistor (P1). The back gates of transistors (N1N, N2N) in the circuit (COMP-N1) and transistors (N1P, N2P) in the circuit (COMP-P1) are commonly connected to the back gate of the transistor (N1). With this structure, in transferring a signal from one terminal (A or B) to the other terminal (B or A) or vice verse, the signal potential is transferred to the back gates of the transistors (P1, N1) at a high speed to increase the signal transfer speed.