A variable attenuator is an attenuator which is formed by coupling two transmission lines having an electrical length of λ/4 corresponding to a wavelength λ of an input signal, has one end of one transmission line as an input terminal, has the other end of the one transmission line as a through terminal, has one end of the other transmission line as a coupling terminal and has the other end of the other transmission line as an output terminal, wherein the variable attenuator has a resistor pair having the same impedance at both the through terminal and the coupling terminal, and has a resistor pair having the same impedance at both the input terminal and the output terminal.