A light source device includes: a light-shielding member defining an opening; a light-guide member located in the opening in a top view and including two or more divided lens portions; and a plurality of light-emitting parts disposed such that each of the plurality of light-emitting parts corresponds to a respective one of the lens portions, each of the plurality of light-emitting parts being configured to be individually turned on. Each of the light-emitting parts has an upper surface serving as a light-emitting surface. The light-shielding member covers a portion of the light-emitting surface of at least one of the plurality of light-emitting parts in the top view. Irradiation areas corresponding to the light-emitting parts are at least partially different from each other.