PURPOSE: To improve the simulation processing efficiency by sorting the instructions of users and inhibiting the execution of such instructions whose simulation results are known.

CONSTITUTION: The instructions of a user 3 are given to a command train production means 11 which produces a command train necessary for actuation of a simulation process 2. This command train is sent to a command sorting means 13 where each command is processed. In other words, each command is inquired by an information storage reference means 12 and then compared with the stored same past command in regard of the argument and the state. Thus, a fact whether the input command can be processed with the information stored in the means 12 or not, is judged. If not, the command is sent to the process 2 by a transmission means 14. The simulation result is received by a reception means 15 and the necessary information is acquired.