The invention provides a gamma curve generation method for reducing calculation amounts and a circuit scale. Three continuous control points are selected from a plurality of continuous control points, and a three-dimensional curve passing those three control points is generated so that the gradient of a tangent to the three-dimensional curve at the second control point can be acquired by interiorly dividing the gradient of a straight line connecting the first control point and the second control part and the gradient of a straight line connecting the second control point and the third control part by a reverse ratio. |