To provide a low noise amplifier which eliminates bias circuit and easily achieve matching gain control.

The low noise amplifier includes: an NMOS transistor and a PMOS transistor where a gate electrode as an input terminal and a drain electrode as an output terminal are common and source electrodes are shortcircuited in AC manner respectively; and a control circuit to adjust a DC potential of the output terminal. The input terminal and the output terminal are connected with each other through a resistance. The resistance may be changed to a variable resistance.