To acquire a constant current generation circuit with small temperature dependency by reducing the change of constant current output due to temperature dependency of resistance built in an integrated circuit, and a constant current setting method for the constant current generation circuit.

By turning on and turning off NMOS (n-channel metal oxide semiconductor) transistors 22 and 23 by turns, a secondary curve, which shows a relation of a synthetic resistance value alpha between the source of an NMOS transistor 24 and a negative-side source voltage GND, and an output current Io1 is calculated with an approximation operation. Subsequently, using the synthetic resistance value alpha to the desired output current Io1 obtained from the secondary curve, a fuse to disconnect is selected from among fuses FB1 to FBn. So as to remove a temperature coefficient of the resistance connected to the selected fuse and the synthetic resistance value alpha of resistances 27 to 29, a fuse to disconnect is selected from fuses FA1 to FAn, and then disconnection is performed. Then, based on an output voltage Vo1 of a constant voltage circuit 2, a fuse to disconnect is selected from among the fuses FB1 to FBn and disconnection is performed.