In a variable attenuator attenuating a signal inputted to an input terminal from a plurality of transmission lines connected in series between the input terminal and an output terminal and outputting the signal from the output terminal, first and second resistance elements to improve an input/output characteristic are connected in parallel respectively to the transmission line connected to the input terminal and the transmission line connected to the output terminal, so that reflection in input/output is sustained by the first and second resistance elements, to obtain a good input/output characteristic, and so that an impedance in a signal line is increased at a time of maximum attenuation without being suppressed by the first and second resistance elements, to obtain a large attenuation amount.