PURPOSE: To continuously obtain various resistance values and to constitute a compact semiconductor device by selecting the mutual connecting part of the FET of a resistance circuit by a switching element and changing the resistance value of the resistance circuit.
CONSTITUTION: Various combined resistances are obtained according to which mutual connecting part of FET 11-14 of a resistance circuit C is selected by pass transistors PT 1 -PT 5 as the respective switching elements. Since a gate voltage control part GC changes the gate voltages of gates G 1 -G 4 of the FET 11-14, the ON resistance of each FET is changed and thus the more various combined resistances are obtained. Further, by successively sending an input signal Ds applied to a shift register Sr from a D flip-flop F 1 to a D flip-flop F 5 , the combined resistance is continuously changed by steps. Thus, the various resistance values can be continuously obtained and a compact device can be constituted.