1. An information processing apparatus, comprising: a control unit including: a main control unit which executes a main process as a processing for controlling said apparatus in a unified manner; and a sub-control unit which executes a task assigned by the main control unit during the execution of the main process, as a sub-process; and an interrupt unit including: an event detector which detects an event occurrence upon which an interrupt task is to be preferentially executed during the execution of the main process; and an interrupt notification unit which notifies said control unit of interrupt information indicative of an interrupt task according to the detected event, wherein the interrupt notification unit conveys the interrupt information to the sub-control unit in said control unit, and wherein the sub-control unit notified of the interrupt information executes the interrupt task specified by the interrupt information, as a sub-process.