A light projection system is a light projection system projecting light on a plurality of processing apparatuses installed in a factory, and includes an acquisition unit acquiring, from each of the processing apparatuses, state information indicating abnormality in the processing apparatus, a light emission unit capable of projecting the light on each of the processing apparatuses, and a projection controller controlling a mode of the light projected from the light emission unit such that the mode of the light reflected from each of the processing apparatuses is changed, on the basis of the state information indicating abnormality.