PURPOSE: To provide high reliability and maintenance to an information processor with a method of correcting a correctable error data, by detecting the number of times of the occurrence of error and then by generating a signal when the number reaches a fixed value.

CONSTITUTION: In normal operation, microinstruction data 2 read out from control memory 1 according to address 9 is used for the control of arithmetic part 8 through change-over circuit 6. Error detecting correction circuit 3 makes a decision on the existence of an error of data 2 and when a correctable error is detected, detection signal 5 reporting it becomes logic "1" to prevent arithmetic part 8 from operating by uncorrected data 2; after the error correction ends, control is so performed by corrected data 4 that operation will be continued normally. Signal 5 makes counter register 11 count up and when the sum of the number of times of the occurrence of correctable errors and fixed value 10 agree with a fixed value, register 11 makes overflow signal 12 into logic "1" to put arithmetic part 8 in a diagnostic receptable state, thereby automatically reporting that the number of times of the error occurrence reaches the fixed value.