A parallelization permission and prohibition management unit of a processor manages the permission or prohibition of the parallelization for each combination of partial spaces in cooperation with another parallelization permission and prohibition management unit of a different processor. Specifically, when any given object is present across the boundary between a first partial space and a second partial space, the parallelization is prohibited between the collision process to be performed by any given processor on the virtual objects in the first partial space and the collision process to be performed by another processor on the virtual object in the second partial space.