A detection system detects corneal reflection to be used to detect an eye gaze of a subject. The detection system includes a detection unit configured to detect reflected light from a subject side irradiated with light from a light source and generate an image based on a detection result of the reflected light, an extraction unit configured to extract a region from the image, the region having an intensity of the reflected light which is equal to or larger than a specific value, and a determination unit configured to, when there are two or more regions, as a extraction result of the region, in which a first region having a characteristic indicating movement over time coexist with a second region having another characteristic indicating no movement over time, determine the first region as the corneal reflection.
