PURPOSE: To accurately segment a fault position when a time-out fault is generated in a computer device.

CONSTITUTION: In a computer device provided with a 2nd unit for executing an instruction outputted from a 1st unit for monitoring the execution of the instruction by a timer, the 1st unit 1 is provided with a timer means 1-1, the 2nd unit 2 is provided with a processing means 2-1 and a timer means 2-2, and when the 2nd unit 2 receives an instruction sent from the 1st unit 1, respective timer means 1-1, 2-2 are driven, then reset based upon the end of instruction processing of the processing means 2-1 and whether a fault position is in the 1st unit or 2nd unit is identified based upon the operation status of respective timer means 1-1, 2-2.