Simulation device for carrying out simulation based on robot program

A simulation device capable of executing a proper simulation without changing a program, while the definition of virtual peripheral equipment and/or a PLC is not necessary. A signal status setting file, which is separated from a robot program, can be executed in parallel with the program, and includes a command for setting or changing a signal status described corresponding to a line in execution of the program, wherein the status is referenced by executing the line of the program. For example, a command of the file, described corresponding to a fifth line of the robot program, commands inputting a signal which indicates that the opening motion of a door is completed. Therefore, when the simulation is executed, in synchronization with the line in execution of the program, the setting or changing of the signal status, described corresponding to the line in execution, is performed.