An imaging device includes a micro lens that collects light from a subject, a light sensing element that generates a signal for performing focusing determination through phase difference detection by sensing subject light collected by the micro lens, and a light blocking portion that is disposed between the micro lens and the light sensing element and performs pupil division for the subject light by blocking a part of the subject light, wherein the light blocking portion is set such that a position of an image forming point of subject light passing through the micro lens and a position of an end portion of the light blocking portion on an entrance side become distant from each other according to a variation in image height.