An overcurrent protection circuit includes a load driver for driving a load, a controller for turning ON and OFF the load driver, a current sensor for measuring a load current flowing through the load, and an add/subtract circuit for performing both an addition operation and a subtraction operation on a previous calculation result or for performing only the subtraction operation on the previous calculation result so as to produce a present calculation result. The addition operation uses an added value depending on the presently measured current. The subtraction operation uses a subtracted value depending on the presently measured current. The controller turns OFF the load driver, when the present calculation result of the add/subtract circuit exceeds a predetermined determination value.