PURPOSE: To generate a plainly displayed three-dimensional graph by inputting parameter information indicating a plane in a three-dimensional coordinate system, two-dimensional coordinate values on the plane, and numerical data.

CONSTITUTION: A three-dimensional graph generating device 1 is provided with a plane information input means 11, a two-dimensional coordinate data input means 12, a three-dimensional coordinate data input means 12, a three- dimensional coordinate transform processing means 13, a three-dimensional coordinate storage means 14, and a three-dimensional graph generation processing means 15. Plane information, two-dimensional coordinate values on the plane, and numerical data of the point are inputted to generate a three- dimensional graph. Thus, the three-dimensional state which is difficult to understand in a two-dimensional graph is easily and plainly displayed.