To provide a lamp structure capable of easily assembling a socket and a stay by a small number of parts, regarding a thin direction indicator lamp for a two-wheeler transversely installing a valve in relation to a lens surface.

The stay is provided with a hole capable of inserting the socket. A groove is provided on a side surface of the stay in the vicinity of the socket insertion hole. A groove is provided from a bottom part of a housing toward an opening part of the housing at a portion of the facing housing. The groove provided on the stay is formed to be inclined to the groove provided on the housing. The housing and the stay are fixed by inserting one piece of a holder having a substantially U-shape in cross section in the groove of the stay and the groove of the housing. At the same time, the socket is held by the other piece of the holder.