An image generation device includes a memory in which a burst length, which is the smallest unit of read/write processing, is large; and an image generation device in which processing efficiency at the time of a memory access does not decrease, even in the case of accessing a rendering buffer for rendering a polygon. Image data is stored in a rendering buffer in block units made up of plural pixels, and image data of pixels corresponding to the polygon is stored in a serial region of the rendering buffer. A valid pixel flag indicating that a valid pixel is present within the block is stored in the rendering information buffer. The rendering buffer is accessed as little as possible based on placement of the valid pixel flags within the block.