A semiconductor integrated circuit, has a current source having one end connected to a power supply and outputting a reference current; a first MOS transistor having one end connected to an other end of the current source and being diode-connected; a second MOS transistor having a gate connected to a gate of the first MOS transistor and passing an output current obtained by current-mirroring the reference current; a first variable resistor connected between an other end of the first MOS transistor and a ground; a resistive component connected between an other end of the second MOS transistor and the ground; and a first operational amplifier fed with a first potential of the other end of the first MOS transistor and a second potential of the other end of the second MOS transistor and outputting a signal for controlling a resistance value of the first variable resistor to equalize the first potential and the second potential, wherein the resistance value of the first variable resistor is controlled based on the output signal of the first operational amplifier.