Abstract: A simulation executing unit 1, an execution list forming unit 2, and an execution list 3 are prepared. The simulation executing unit 1 does not execute all of function models 4 every cycle, but executes only such a process operation described in the execution list 3 formed by the execution list forming unit 2. Upon receipt of notification as to a status change sent from each of hardware, the execution list forming unit 2 dynamically forms the execution list 3 of process operations which are executed every cycle in conjunction with the status change. As a result, the simulation executing unit 1 performs such a process operation suitable for the status change every cycle so as to perform a simulation in a high speed.