A variable attenuation microwave attenuator includes input and output terminals, a high-pass filter having an electrical length of 90.degree. and transmitting signals with frequencies higher than a cut-off frequency, a first variable resistor connected between the input terminal and an input end of the high-pass filter, and a second variable resistor connected between an output end of the high-pass filter and the output terminal, wherein input signals applied to the input terminal are attenuated by the first and second variable resistors before and after the high-pass filter. Therefore, the variable attenuator can be a lumped parameter circuit, i.e., the high-pass filter including two inductors and a capacitor, without using a transmission line as in the prior art device, so that the size of the device is significantly reduced. Further, since the resistance values of the first and second variable resistors do not change discretely but change continuously, a lot of different values of attenuation can be obtained with high precision. As a result, the gain (attenuation amount) can be controlled with high precision.