PURPOSE: To generate an output potential which is at a sufficient level and resistant to the variation of a manufacture process by increasing an input potential of an MOS transistor (TR) operated in outputting a power potential level.

CONSTITUTION: When an activated signal 1 goes from a low level to a high level with a signal ' at a high level (power voltage VCC and with an input I', e.g., between inputs I and I' at a low level, nodes N1, N2 start transition to a high level. The node N2 restores immediately to a low level because an MOS TRQ22 is conductive. On the other hand, the node N1 progresses a low level state of the high level node N2 and a TRQ11 is made nonconductive. Then the signal VN1 of the node N1 charges a node N1'. The signal VN1 becomes an input of a bootstrap circuit B1 at the same time and a signal VN9 of high level is generated at a node N9. The signal VN9 increase the potential at the node N1' to a voltage level high than the VCC via a capacitor C2. Thus, the level at an output OUT becomes a level nearly equal to the voltage VCC.