For improvement in switching speed, there is provided a Schmit trigger circuit comprising a high-voltage supply line, a low-voltage supply line, a series combination of a bipolar transistor and a resistor provided between the high-voltage supply line and the low-voltage supply line, the bipolar transistor having a base node connected to an input terminal, an intermediate node provided between the bipolar transistor and the resistor, a logic gate having an output node and two input nodes connected to the input terminal and the intermediate node, respectively, and a field effect transistor operative to establish or block a current path between the intermediate node and one of the high-voltage supply line and the low-voltage supply line, the field effect transistor having a gate node connected to the output node of the logic gate.