To provide an overcurrent protector capable of making a short circuit current small enough even at an abnormal state with no failure of starting a power supply.

An overcurrent protector has an overcurrent protective circuit 21 with an error amplifier 21a to generate an output signal for determining a driving pulse width of a switching element 22 when an overcurrent from a switching power supply 1 through loads 16a to 16c is detected. In addition, the overcurrent protector has comparators 31 and 32 having each comparison voltage to change a comparison level Vcr in the error amplifier 21a according to an output voltage level Vfef1, and a flip-flop 33 for holding the output from comparators 31 and 32.