To provide an electric power supply circuit capable of preventing a rapid electric power from being output into an inverter circuit although it is the electric power supply circuit to supply electric power to the inverter circuit by a PWM method.

The electric power supply circuit is equipped with a first electric power input terminal and a second electric power input terminal in which prescribed electric power is respectively input, a transistor for output which is an NPN type transistor and in which the base is connected to the second electric power input terminal, a collector is connected to the first electric power input terminal, and an emitter is connected to a prescribed inverter circuit, and a switching part to switch ON/OFF of the base voltage in the transistor for output. This is the electric power supply circuit in which electric power is supplied to the inverter circuit by adjusting a duty ratio through timing of switching. This is made as the electric power supply circuit in which a coil is connected between the first electric power input terminal and the collector of the transistor for the output.