A power supply circuit comprising: a rectifier to rectify a voltage output from a power source; a power factor compensation circuit including a plurality of reactors (31a, 31b) to store and output currents output from the rectifier, a plurality of switches (34a, 34b) switched such that the currents are stored in the reactors (31a, 31b) or are output, and a plurality of current detectors (33a, 33b) to output voltages according to the currents from the reactors (31a, 31b); and a power factor compensation circuit controller to control switching of the switches (34a, 34b) and to control a power factor compensation operation, characterized by a power factor compensation circuit protection circuit to receive the voltages output from the plurality of current detectors (33a, 33b) and to stop the operation of the power factor compensation circuit controller if at least one of the voltages output from the plurality of current detectors (33a, 33b) is abnormal, wherein the power factor compensation circuit protection circuit includes a plurality of comparators (71a, 71b) to receive the output voltages of the plurality of current detectors (33a, 33b) and a reference voltage, each of the comparators (71a, 71b) is configured to compare the output voltage with the reference voltage and to output an error signal according to the result of comparing the output voltage with the reference voltage, and when the error signal is output from at least one of the plurality of comparators (71a, 71b), the power factor compensation circuit protection circuit is configured to stop the operation of the power factor compensation circuit controller. a rectifier to rectify a voltage output from a power source; a power factor compensation circuit including a plurality of reactors (31a, 31b) to store and output currents output from the rectifier, a plurality of switches (34a, 34b) switched such that the currents are stored in the reactors (31a, 31b) or are output, and a plurality of current detectors (33a, 33b) to output voltages according to the currents from the reactors (31a, 31b); and a power factor compensation circuit controller to control switching of the switches (34a, 34b) and to control a power factor compensation operation, characterized by a power factor compensation circuit protection circuit to receive the voltages output from the plurality of current detectors (33a, 33b) and to stop the operation of the power factor compensation circuit controller if at least one of the voltages output from the plurality of current detectors (33a, 33b) is abnormal, wherein the power factor compensation circuit protection circuit includes a plurality of comparators (71a, 71b) to receive the output voltages of the plurality of current detectors (33a, 33b) and a reference voltage, each of the comparators (71a, 71b) is configured to compare the output voltage with the reference voltage and to output an error signal according to the result of comparing the output voltage with the reference voltage, and when the error signal is output from at least one of the plurality of comparators (71a, 71b), the power factor compensation circuit protection circuit is configured to stop the operation of the power factor compensation circuit controller.