According to an aspect, a detection device includes: a light source device; an object placement member on which an object to be detected is placed; a liquid crystal shutter having divided regions; and an optical sensor having detection regions arranged in a plane. One of the detection regions includes one or more photodetection elements. The light source device includes a light-shielding wall disposed between two adjacent light-emitting elements out of the light-emitting elements. The divided regions in the liquid crystal shutter are each capable of being switched between a light-transmitting state and a non-light-transmitting state for each of the divided regions, and the light-emitting elements are each capable of being switched between a lit state and an unlit state for each of the light-emitting elements. The respective light-emitting elements, the respective divided regions of the liquid crystal shutter, and the respective detection regions overlap when viewed in the first direction.