PURPOSE: To maintain an excellent switching characteristic even against driving of a large load capacity by constituting a titled circuit so that one of an npn type or pnp type transistor goes to a cutoff state or a conducting state, and it is operated as an emitter-follower circuit having a low driving impedance characteristic, when an output level is varied.
CONSTITUTION: A CMOS logical circuit is a logical circuit to which an npn type trasistor Q5 in which the collector is connected to a power source 1, the base is connected to an output point 5' of the CMOS logical circuit, and the emitter is connected to an output terminal 5, and a pnp type transistor Q6 in which the emitter is connected to the output terminal 5, the base is connected to the base of the npn type transistor Q5, and the collector is connected to a power source 2 is added. Also, as for the circuit consisting of the npn type transistor Q5 and the pnp type transistor Q6, one of the npn type transistor Q5 and the pnp type transistor Q6 goes to a cutoff state, in the stationary state, therefore, no power source current flows, and the power consumption is extremely small.