An image forming apparatus executes the steps of: calculating an end time of the job of which execution is instructed, and determining if the end time of the job is before the start time of power outage; specifying, if it is determined that the end time of the job is not before the start time of power outage, a part of processing of the job that can be completed before the start time of power outage; starting the job, if it is determined that the end time of the job is before the start time of power outage; and starting the part of processing of the job if it is determined that the end time of the job is not before the start time of power outage. Thus, abnormal termination of an active job due to power outage can be prevented.