A task management apparatus comprises a plurality of processors, and correspondingly stores, a plurality of tasks to be assigned to the processors within a predetermined period of time, and temporal groups each of which is assigned to the plurality of the tasks. The task management apparatus assigns one of the tasks to one of the processors. After having assigned the task, the task management apparatus assigns, to the one of the processors that has finished processing the assigned task, the other tasks that are in correspondence with the same temporal group as the temporal group with which the assigned task is in correspondence, before assigning the tasks that are not in correspondence with the temporal group.