PURPOSE: To recognize which input data is that an error occurred among plural input data by inhibiting the update of a selector switching signal being held in a pass indicator register by transmitting a hold signal.

CONSTITUTION: When an error is detected in a reading data 12 of a register file with an output selector 11 by a parity check circuit 14, the update of a selector switching signal 9 indicating the input data that an error occurred being held in a path indicator register 10 by a hold signal 17 transmitted from an error indicator flag register 15 is inhibited. Therefore, when an error occurs in the reading data 12, the input data where the error occurred is one among the plural input data is decided by investigating the selector switching signal 9 being held in the path indicator register 10. Thus, when an error is detected by the parity check, which input data has trouble is recognized.