To provide a graphics plotting system capable of reducing the load on a bus, and realizing a high speed operation.

A command recognizing means 201 recognizes a command and data transferred from a CPU 100, and transfers the data to a data storage processing means 202 and a third vertex processing means 203. The data storage processing means 202 stores the data of first and second vertexes in a storage means (system memory) 204, and the third vertex processing means 203 stores the data of the third vertex in the storage area of the third vertex of the storage means 204 through the data storage processing means 202, and reads the first vertex and second vertex data, and transfers each first - third vertex data to a same data judgment processing means 205 so that whether or not those three vertexes are the same data can be judged. Then, the data are transferred to a same data output processing means 206 or a non-same data output processing means 207 according to the judged result. The same data output processing means 206 transfers the data as data common to the three vertexes, and the non-same data output processing means 207 transfers the data of each vertex to a rendering engine 300.