To provide a downsized and inexpensive power supply unit having an inductor with a simple structure requiring no secondary winding.

This power supply unit 100 includes: a diode bridge 2 which outputs a pulsating voltage including a pulsating component from a positive electrode by rectifying closed AC power supply; a boosting chopper circuit 70 which stores energy for boosting the pulsating voltage output by the diode bridge 2 and includes an inductor 7 equipped with an intermediate terminal c for the output of a driving signal for driving other elements at some midpoint of a winding; a current-limiting element 3 connected between the diode bridge 2 and the inductor 7; and a switching element 4 which is connected in parallel to the current-limiting element 3 and turns on based on the driving signal output from the intermediate terminal c.