PURPOSE: To improve the utilizing rate of a power supply voltage by deciding entirely separately a potential at an input terminal and an output terminal.

CONSTITUTION: An input signal from a signal input terminal 21 is impressed to a base of transistors (TR) Q21, Q22 and an emitter current is fed to a common emitter by giving a constant current source I3 thereto. Variable current sources I1, I2 having an equal value are connected respectively to a collector of the TRs Q21, Q22 and the amplitude of the current sources I1, I2 is in the relation of I1= I2>1/2I3 compared with the I3. An emitter of TRs Q23, Q24 being buffers is connected respectively to a collector of the TRs Q21, Q22, a base is fixed to a constant potential VB2 and the collector becomes a current output terminal 22 of opposite polarity respectively. A DC current flowing to the terminal 22 by the circuit generates a level shift voltage having a value multiplied with a load resistor and the potential is permitted up to the power supply voltage.