Abstract: This disclosure concerns semiconductor integrated circuit includes a semiconductor substrate; a plurality of well regions formed on one surface of the semiconductor substrate and electrically isolated from each other; a plurality of MOS transistors formed in the well regions; and a substrate bias generator applying substrate biases to the individual well regions based on actually measured process-derived variance of the MOS transistors in threshold voltage to bring the threshold voltages of the respective MOS transistors into conformity with a normal threshold voltage.