PURPOSE: To provide the information processor with high operability while maintaining the reliability of the information processor without requiring much time to confirm the normality of the fault detection circuit even when the amount of the fault detection circuit is increased by adding a detection section detecting circuit to each detection circuit and automatically restarting the information processor when the fault is attributed to the only detection circuit.

CONSTITUTION: Detection section detecting circuits 24-26 are provided with a detection duplex section and a detection comparison section. For example, when a detection circuit 21 fails, the information '1' of an error holding flip-flop showing that the detection comparison section detects the noncoincidence of comparison and all the input information for the detection circuit 21 and the detection duplex section are included in the information of a scanning path 15 extracted by an information extracting section 3. A data judgement section 4 can judge the fault of the detection circuit 21 because the input information of it is normal based on the information. When the fault is attributed to the detection circuit 21, a signal is sent to a restart section 30 to operate it.