A light source device includes a primary light source unit and a light converting unit. The primary light source unit includes a primary light emitting portion. The light converting unit includes a light converting member and a secondary light emitting portion. In the two-dimensional shape of the secondary light emitting portion projected on a surface perpendicular to the optical axis of primary light, the length of the minimum width of the two-dimensional shape passing through the center of gravity of the two-dimensional shape is different from the length of the maximum width of the two-dimensional shape passing through the center of gravity.