PURPOSE: To generate a constant current having no temperature dependency or desired temperature dependency with circuit configuration more simplified than the conventional configuration.

CONSTITUTION: An emitter resistor 30 is connected to one of a pair of band gap transistor means 10 and 20, of which the emitter current density is different, connecting their bases in common and a parallel additive resistor 40, of which the resistance value having positive temperature dependency, is connected parallelly to those means. Then, a driven current If of a current mirror circuit for receiving a current supplied from a current supply transistor 50 to both the means 10 and 20 and the parallel additive resistance 40 as a reference current Io is extracted as a constant current output Io of a constant current circuit 70. Thus, the positive temperature dependency provided for a current I1 or I2 to flow to both the means 10 and 20 is canceled or partially compensated by the negative temperature dependency of a current to flow to the parallel additive resistor 40 and the desired temperature dependency is given to the constant current output Io.