An image generating device comprises an acquisition unit which acquires an image drawing instruction for drawing an elliptical radial gradation from accepted target data, an extraction unit which extracts elliptical shape parameters and gradation pattern parameters from the acquired image drawing instruction, a transformation matrix generating unit which generates a transformation matrix for transforming an elliptical shape specified by the elliptical shape parameters into a perfect circular shape based on the elliptical shape parameters, an inverse matrix calculating unit which calculates an inverse matrix of the transformation matrix, a transformation unit which transforms the gradation pattern parameters using the transformation matrix, a drawing unit which draws a gradation for the perfect circular shape based on the transformed gradation pattern parameters, and a gradation generating unit which generates the elliptical radial gradation by inversely transforming the perfect circular shape (including the gradation drawn by the drawing unit) using the inverse matrix.