Antialiasing image generation apparatus for selecting an antialiasing technique to be applied to a pixel using pixel data

An antialiasing image generation apparatus includes a distribution information acquisition unit configured to acquire distribution information that indicates the distribution of a plurality of Z values, a polygon data expansion unit configured to expand polygon data into display coordinates, a representative point pixel data generation unit configured to generate pixel data including a Z value at a representative point, an antialiasing technique selection unit configured to select an antialiasing technique using the Z value included in the pixel data and the distribution information, and an antialiasing processing unit configured to generate a graphics image by performing antialiasing processing on the pixel according to the selected antialiasing technique.