To provide a simulation device which carries out interference check between a robot, a workpiece, and a peripheral device with high accuracy.

The simulation device A comprises a data acquiring section 11 and a simulation section 12. The data acquiring section 11 receives input data inclusive of robot shape information and robot action performance, workpiece shape information and information indicative of workpiece machining location, peripheral device shape information, and layout information. The simulation section 12 configures a robot model 21, a workpiece model 22, and a peripheral device model 23 in a virtual space, and carries out interference check between the robot, the workpiece, and the peripheral device by a simulation performed by operation of the robot model 21 in the virtual space. Herein in the robot model 21 configured by the simulation section 12, an end effector at the tip thereof is displayed by a shape that is set a predetermined dimension larger than a size determined according to the robot shape information.