A multi core system for allocating a task generated from a control system program to an appropriate CPU core and executing the task includes a trial-execution instructing part configured to cause a second CPU core to trial-execute a task which a first CPU core executes before the multi core system transfers the task from the first CPU core to the second CPU core and causes the second CPU core to execute the task, a determining part configured to determine whether an execution result by the first CPU core matches an execution result by the second CPU core, and an allocation fixing part configured to fix the second CPU core as the appropriate CPU core to which the task is allocated if the determining part determines that the execution result by the first CPU core matches the execution result by the second CPU core.