An information processing system performs a plurality of tasks within a specific time interval. The system includes a bus, a plurality of processors which transfer data via the bus, and a unit for performing a scheduling operation of determining execution start timing of each of the tasks and at least one the processors which executes the tasks, based on cost information concerning a time required to perform each of the tasks and bandwidth information concerning a data transfer bandwidth required by each of the tasks, to perform the tasks within the specific time interval without overlapping execution terms of at least two tasks of the tasks, the two tasks requiring data transfer bandwidths not less than those of the others of the tasks.