This light source unit includes a light source, a collimator lens, a support body, and an adhesive agent. The collimator lens is configured to collimate laser light emitted from the light source. In the support body, a first support portion configured to support the light source and a second support portion configured to support the collimator lens are integrally molded with each other by use of a synthetic resin. The adhesive agent is attached by a larger amount between the second support portion and a second face which is on an opposite side to a first face on the light source side of the collimator lens, than between the second support portion and the first face.