A video game apparatus includes a CPU that generates a game screen that depicts player character movement while a game is being played. In addition, the CPU controls the production of sounds that seem to eminate from one or more sound objects displayed on the game screen. When a plurality of the sound objects of the same kind exist on the game screen, the CPU computes sound volume data of the sounds produced by the respective sound objects and divides the computed sound volume data into components of right sound volume data, left sound volume data, and surround sound volume data. Using respective sound components from all the displayed sound objects, the maximum components are extracted and localization data and sound volume data are computed. Based on the computed localization data and sound volume data, the composite sound of a sound object is output.