A dropper type regulator of the invention, in which a semiconductor device
is connected in series between a DC power supply and a voltage output
terminal, extracts a second voltage from the first voltage of the DC
power supply; when the driving voltage of the semiconductor device is
detected as being larger than a preset first threshold value, the voltage
difference occurring between the input and output terminals of the
semiconductor device is detected, and when this voltage difference is
detected as being larger than a second threshold value, an overload
protection circuit performs overload protection.