PURPOSE: To prevent an output signal from being changed in a state change between the active and inactive states by disconnecting an inner node and an output node before a switch means inserted to a power voltage supply path is turned off.

CONSTITUTION: When a selection signal changes from L to H, a transfer gate 30 is turned off before a signal CE1' is changed, the internal node 3 is disconnected from the output node 23 of an inverter 20. A signal Out of the node 3 after the disconnection is set to the original level by a latch signal of a latch circuit 5. Then the signal CE1' changes from L to H and an MOSFET24 is turned off. Even when a selection signal changes from H to L, the gate 30 is turned on before the signal CE1' is changed. Then the signal CE1' changes from H to L, the FET24 is turned on, and a signal of the node 23 corresponds to a signal in response to the input signal In. When the level of the signal at the node 23 and of the circuit 5 is the same, the level of the output Out is unchanged.