A rendering device according to the present invention comprises an information acquiring unit for acquiring system information or rendering object information, a control point generating section for setting a curved surface interpolating level serving to determine number of control points for creating a curved surface or a curved line based on the acquired information and thereby generating the control point in accordance with the curved surface interpolating level, and a curved surface creating section for creating the curved surface based on the control point, wherein an operation quantity for rendering the curved surface of a display object is dynamically changed based on the acquired information.