A logic circuit comprises at least one signal input terminal, an output terminal, an output circuit including a first bipolar transistor coupled between the output terminal and a reference potential terminal, to discharge the output terminal, and an MOS type logic circuit for supplying to the base of the first bipolar transistor a signal of a level corresponding to an input signal supplied to the at least one signal input terminal. The logic circuit further comprises a control MOS transistor coupled between a power source terminal and the base of the bipolar transistor, for supplying part of the base current to the bipolar transistor in response to a signal at the output terminal.