PURPOSE: To propagate a signal from the input to the output at a high speed by controlling the propagation of the signal from the input to the output with a bipolar transistor (TR).

CONSTITUTION: The circuit is provided with a 1st bipolar TR 11 whose collector connects to an input terminal 4 and whose emitter connects to an output terminal 6 and a 2nd bipolar TR 12 whose collector connects to the output terminal 6 and whose emitter connects to the input terminal 4. Then the TRs act like switches to control the switching between the input terminal 4 and the output terminal 6 with a control signal fed to a control terminal 5. Thus, the bipolar TRs 11, 12 having a small conduction resistance being 1/10 or below the conduction resistance of a MOS TR are used between the input terminal 4 and the output terminal 6 to apply switching between the input and output terminal, then a signal fed to the input terminal 4 is propagated to the output terminal 6 at a high speed.