Abstract: Sound processing technology is provided whereby sound can be changed to correspond to changes in the viewpoint for generating a virtual image. The sound processing device generates sound corresponding to a virtual image obtained by observing a virtual space from any one of a plurality of viewpoints set inside this space. It comprises sound generation conditions determining means for identifying the viewpoint of the virtual image currently being generated and determining sound generation conditions for the sound corresponding to the identified viewpoint, and sound generating means for generating sound based on sound signals in accordance with the determined sound generation conditions determined by the sound generation conditions determining means. A very realistic environment is provided to a player viewing the image.