A display device includes a display region, a peripheral region, a first substrate, a second substrate having a side surface, a liquid crystal layer arranged between the first substrate and the second substrate, a side light source device mounted on a front surface of the first substrate and arranged at a position facing the side surface of the second substrate, and a light reflection film formed on either a side with a back surface of the first substrate or a side with a front surface of the second substrate. The light reflection film covers the entire display region.