A light emitting module comprising a light guide plate and a light source. The light guide plate has a polygonal shape with a plurality of corners in a plan view. The light guide plate has a first primary face which serves as an emission face, a second primary face opposing the first primary face, and a recessed portion in the second primary face. The light source is disposed in the recessed portion. The recessed portion has an opening on the second primary face, and a bottom face having a polygonal shape in a plan view. The light source has lateral faces along sides of the bottom face of the recessed portion. In a plan view, diagonal lines connecting opposing corners of the first primary face intersect with the sides of the bottom face of the recessed portion.