PURPOSE: To obtain the resistance attenuator whose attenuation is made variable in which three resistors being components of a π or T-shaped resistance attenuator are formed respectively with plural resistors and a prescribed resistor is short-circuited in response to the attenuation among the division resistors.

CONSTITUTION: Two resistors 5, 6 are provided between an input terminal 1 and an output terminal 2, a series circuit of resistors 7, 8 is loaded between a connecting point of the two resistors 6 and ground. For example, then an attenuator whose attenuation quantity T2 for a microwave propagated from the input terminal 1 to the output terminal 2 is obtained by short-circuiting the resistors 5, 8. Furthermore, the attenuator whose attenuation is T1 is obtained by short-circuiting the resistors 6, 7 conversely. Furthermore, the attenuator whose attenuation is T1.T2 is obtained when any of the resistors 5-8 is not short-circuited. Thus, the variable resistance attenuator whose attenuation is variable from T1 to T1.T2 is obtained.