Provided are a variable field effect transistor (FET) designed to suppress a reduction of current between a source and a drain due to heat while decreasing a temperature of the FET, and an electrical and electronic apparatus including the variable gate FET. The variable gate FET includes a FET and a gate control device that is attached to a surface or a heat-generating portion of the FET and is connected to a gate terminal of the FET so as to vary a voltage of the gate terminal. A channel current between the source and drain is controlled by the gate control device that varies the voltage of the gate terminal when the temperature of the FET increases above a predetermined temperature.