Abstract: It is an object to speedily generate a hidden surface removed image, by dividing one picture frame into a plurality of rectangular blocks and by repeating generation of a hidden surface removed block image. A block segmenting section 22 seeks, on the basis of primitive information from a primitive information setting section 21, in-block span information obtained when a primitive is segmented into a collection of in-block spans so that a projected image of the primitive completely falls in one block. The block segmenting section also seeks block information indicating a block including a projected image of the primitive projected onto a picture plane.