A simulation system having multiple peripherals that communicate with each other. The system includes a weighted graph with weights set as communication times. The peripherals are represented as nodes and connection paths are represented as edges. Among the communication times in the loop, the minimum time is set as first synchronization timing. Timing with an acceptable delay added is set as second synchronization timing. Timing set by a user to be longer than the first and second timings is set as third synchronization timing. The third synchronization timing is used in a portion where the timing is usable, thus synchronizing the peripherals at the longest possible synchronization timing.