According to an aspect, a detection device includes: a substrate; a plurality of photodiodes provided to the substrate and arranged in a first direction; a plurality of lenses provided so as to overlap the photodiodes; and a light-blocking layer provided between the photodiodes and the lenses and having a plurality of openings. More than one of the openings is provided in each of regions overlapping the respective photodiodes, and an arrangement direction of the openings in each of the regions overlapping the respective photodiodes is at an angle to the first direction.