It is an object of the present invention to provide a variable gain amplifier of which impedance does not change when gains are switched. A transistor is turned on in a high-gain state and transistors are turned on in a low-gain state to switch between the gains, the area of the transistor is made equal to the area of the transistor to keep the same output load conditions and the same output impedance both in the high-gain state and the low-gain state. While the input impedance of a transistor becomes high because the transistor in a high-gain path is turned off in the low-gain mode, current passes through a transistor to lower the impedance of the collector of a transistor and, as a result, the input impedance is kept the same both in the high-gain state and the low-gain state.