In a laser light source device having an optical element and a plurality of heat sinks on which the optical element is joined directly or through a sub mount, and obtained by joining the heat sinks to each other by means of a joining material such that optical elements are optically directly joined to each other, the laser light source device includes a groove portion extending in a direction substantially orthogonal to an optical axis of light in the laser light source device on any one of a joining surface of the optical element or the sub mount to join with the heat sink and a joining surface of the heat sink to join with the optical element or the sub mount.