PURPOSE: To enable an interruption request with higher priority level to be immediately accepted without an interruption prohibiting state for the interruption request with priority level.

CONSTITUTION: An instruction execution control part 114 performs such control that a flag which stores inhibition/permission for the acceptance of all the interruption requests is provided in a PSW 16, and when the interruption request with priority level is accepted, the flag is set in a permitting state, and when the interruption request without priority level is accepted, the flag is set in a inhibiting state. The interruption request with higher priority can be accepted without the interruption inhibiting state for the interruption request with priority level. No multiplex interruption processing is required for the interruption request without priority level such as interruption for debugger.