The present invention causes a computer to function as a virtual space generating unit, a game screen displaying unit and a fluid displaying unit. The fluid displaying unit displays pseudo three-dimensional representation of fluid in a virtual space on a game screen. And the fluid displaying unit includes a two-dimensional data acquiring unit for acquiring two-dimensional data including a two-dimensional map by processing at least part of the surface of a three-dimensional object into a two-dimensional manner and a simulating unit for simulating a flow of the fluid on the two-dimensional map and displaying a simulating result on the surface of the object. The two-dimensional map includes height information of each point on the surface of the object. The simulating unit simulates the flow of the fluid on the two-dimensional map based on the height information.