This invention provides a data processing system capable of performing an interrupt exception handling routine as many times as the number of times of occurrence of a request event for the same interrupt exception handling routine if the request event occurs a plurality of times. A software interrupt counter or a hardware interrupt counter for retaining the number of times of occurrence of an interrupt request generation event counts up when a software processing which generates a software interrupt or a hardware event that generates a hardware interrupt occurs, and counts down when a CPU performs a processing for removing the interrupt request. If the value of the software interrupt counter and the value of the hardware interrupt counter are not zero, a software interrupt request signal and a hardware interrupt request signal to the CPU are asserted.