A load driving device according to an aspect of the present invention may includes an output transistor and a load connected in series between first and second power supply lines, a protection transistor connected between a gate of the output transistor and the second power supply line, the protection transistor turning on the output transistor when a polarity of a power supply connected between the first and second power supply lines is reversed, and a resistor arranged on a line, which supplies a voltage to a back gate of the protection transistor.