A light emitting device includes a carrier, a light emitting element disposed and electrically connected to the carrier, and a transparent plate disposed on the carrier and including a flat-portion and a lens-portion. The lens-portion covers the light emitting element and has a light incident surface, a light emitting surface, a first side surface and a second side surface. The light emitting element is suitable for emitting a light beam. A first partial beam of the light beam passes through the light incident surface and leaves from the light emitting surface. A second partial beam of the light beam passes through the light incident surface and is transmitted to the first side surface or the second side surface, and the first side surface or the second side surface reflects at least a part of the second partial beam of the light beam to be passed through the light emitting surface.