To provide an interruption priority order changing system capable of improving the reliability and throughput of each interruption request and improving the reliability of a device system.

An interruption controller 1 has a priority order determination function and an interruption arbitration function for n (n≥2) interruptions. Each of performance monitors 4-1 to 4-n has three counters and counts up interruption processing time from the reception of interruption processing by a CPU 2 up to the completion of the interruption processing, reference time for sampling the interruption processing state of the system and the number of times of time-out of the interruption processing. The CPU 2 monitors the interruption processing time and the time-up frequency state, acquires the quantitative data of interruption processing per fixed time and sets the priority order without causing any time-out in all the interruption processing by allocating the priority of an interruption request frequency causing time-out to a higher level.