PROBLEM TO BE SOLVED: To provide a method and a device enabling an incubation processing for only a female egg, by determining sex of a sperm egg from shape data thereof.SOLUTION: Sex is determined by detecting a difference of image data showing that each rotation direction of change of a vector caused by change of a contour 1 of an outer shell surface around a long axis of a sperm egg 10, and of change of each area of a two-dimensional fourth quadrant following inclination of a short axis, is different according to sex.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2019,JPO&INPIT【課題】有精卵の外形データから雌雄の鑑別を行い、雌卵のみの孵化処理を可能とする方法と装置の提供。【解決手段】有精卵10の長軸周りにおける外殻表面の輪郭1の変化によるベクトルの変化と短軸の傾斜に伴う二次元面4象限の各面積変化の回転方向が雌雄で異なることを示す画像データの相違を検出して雌雄を鑑別する。【選択図】図1