A differential amplifying circuit includes first and second differential transistor pairs, first and second constant current sources, first and second current mirror circuits and first and second output transistors. The differential amplifying circuit also includes a feedback circuit configured to perform feed-back operations to the first and second current mirror circuits to restrain reduction of gate voltages of the output transistors. The constant current sources are configured to increase bias currents in response to reduction of the gate voltages of the output transistors.