To provide a protection circuit for outputting an instruction for blowing fuses connected to power supplies, when abnormality is detected in the voltages from the power supplies, and making constant the time starting from the detection of the abnormality to the blowing of the fuses.

The protection circuit outputs the instruction for blowing the fuses F1, F2 connected to the power supplies 111-1-111-4, when the abnormality is detected in the voltages from the power supplies 111-1-111-4, and has time control means 221-1-221-4, 222, 223 for detecting the states of the voltages from the power supplies 111-1-111-4 and controlling the time starting from the detection of the abnormality in the voltages from the power supplies until outputting of the instruction for blowing the fuses F1, F2 in response to the state.