A variable gain amplifier is provided that can obtain a wide range of gain
variation and suppress the deterioration of linearity when switching
between amplifying transistors. The variable gain amplifier includes a
plurality of cascode amplifiers each including an amplifying transistor
and a plurality of cascode transistors connected in a cascode arrangement
to an output terminal of the amplifying transistor. The plurality of
cascode amplifiers are connected through attenuators. The variable gain
amplifier further includes a first controller that controls ON/OFF
operations of the plurality of cascode transistors included in each
cascode amplifier; and a second controller that controls ON/OFF
operations of a plurality of amplifying transistors, only one of which is
included in each of the plurality of cascode amplifiers, such that only
selected one of the plurality of amplifying transistors is turned on.