A simulation control section 210 of an NC machining simulation apparatus 10 computes a movement path of a mechanical element when performing simulation. A ring buffer 270 memorizes the movement path of the mechanical element. In response to a replay instruction, the simulation control section 210 reads the movement path from the ring buffer 270. The simulation control section 210 then displays the mechanical element on a display device 190 as a solid model based on the movement path for replaying the simulation.