A processing device for performing a geometry process performed as preprocessing for rendering a three-dimensional obj ect on a display by modeling the three-dimensional obj ect using a polygon mesh. The geometry process includes a vertex process that is performed for each of the vertices of the polygon mesh by a different one of a plurality of processors, and processed vertex data obtained by the vertex process is notified among the processors so that a polygon process can be performed in each of the processors. Since each processor can continuously perform the polygon process immediately after the vertex process, it is possible to suppress the occurrence of the unbalance of timing in performing the vertex process and the polygon process, thereby efficiently performing computation while minimizing the wasteful idle time of the processors.
