A periodic process performing system includes a system processor to which a first periodic real-time process, which starts to be executed starts for each of a first time interval from a first start time, is assigned; a wakeup logic which provides the system processor with a first state capable of executing the first periodic real-time process; and a counter which supplies a first tick signal to the wakeup logic for each of the first time interval from a second start time earlier than the first start time, and supplies a second tick signal to the system processor for each of the first time interval from a third start time between the first start time and the second start time.