the present invention provides a semiconductor device in which an adjustable range of a resistance value of a variable resistance circuit is large . the semiconductor device has an output buffer including a plurality of sets of resistance elements and a plurality of sets of transistors , a plurality of replica circuits , and a plurality of sets of operational amplifiers , and drain currents of the plurality of sets of transistors are adjusted so that output impedances of the output buffer become predetermined values . therefore , even in the case where the resistance values of the resistance elements largely fluctuate due to fluctuations in manufacture process and the like , the output impedances can be set to predetermined values .