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, a first light blocking unit that performs pupil division by blocking a portion of the subject light, and a second light blocking unit that is disposed between the first light blocking unit and the micro lens, and blocks the portion of the subject light which is incident to the first light blocking unit, wherein an aperture area of the second light blocking unit is smaller than an aperture area of an image generation pixel.