A detection apparatus includes: plural light emitting sections that are disposed in a row and that emit parallel light to a passage region, over which an object passes, in a time-staggered manner; one or more light receiving sections that receive the parallel light reflected by or having transmitted through the object, a number of the light receiving sections being less than a number of the light emitting sections; and a detection section that detects at least one of edges of the object and edges of a portion of the object with a different reflectivity or transmittance in accordance with an intensity distribution of the parallel light received by the light receiving sections.