The present invention is an image processing method for drawing an integrated shaping model which has a plurality of models linked by a hierarchical structure, where at least a first models has a plurality of vertices constituting polygons and at least the position of a first vertex is influenced by positions of a plurality of models and weight values from these models. The data (110) of the integrated shaping model comprises: format data of a common vertex buffer which stores data on the plurality of vertices in the plurality of models for each model; a vertex list which is created for each model which influences the vertices and has vertex data specified by a vertex ID in the common vertex buffer; and a polygon list which is created for each model having the polygon and includes polygon data where the vertex ID is attribute data. The image processing method comprises steps of: generating the common vertex buffer corresponding to the plurality of models in the sequence of tracing of the hierarchical structure according to the format data; generating model matrix data where the positions of the models are set based on the game progress data; generating common vertex data by executing the matrix calculation for generating vertex data after movement according to the model matrix data weight calculation for integrating the weight values from the models to the vertex data after movement, for the vertex data of the vertex list of the models, and by storing or adding this operated vertex data to areas according to the vertex IDs in the common vertex buffer; and rendering the polygon according to the common vertex data.