Provided are a photoreactive compound represented by formula (1), a liquid crystal alignment layer using the compound, a method of manufacturing the alignment layer, and a liquid crystal display device including the alignment layer: ##STR00001## where n is an integer of 20-1000; m is an integer of 1-5; and R is a hydrogen atom, CN, a C1-C5 alkyloxy group, a halogen atom, or a maleimide group.