[Problem] To multiplex white illumination light and narrow band light using the light efficiently by equalizing the angles of emission of the two types of light while preventing an increase in production costs. [Solution] This light source device is provided with: a white illumination light source for emitting white illumination light； one or more narrow-band light sources for emitting narrow band light； a multiplexing optical system for multiplexing the white illumination light and the narrow band light； a condensing optical system for coupling the multiplexed white illumination light and narrow band light into a light guide that is provided in an image acquisition device and that leads illumination light into the image acquisition device； and a light quantity distribution adjustment element that is provided on an optical axis between the narrow-band light source(s) and the multiplexing optical system, and adjusts the light quantity distribution of the narrow band light. The light guide is either a bundle-type light guide in which multi-mode optical fibers are bundled or a liquid light guide the inside of which is filled with a liquid. The light quantity distribution adjustment element adjusts the light quantity distribution of the narrow band light such that the emission angle distribution of the narrow band light after passing through the light quantity distribution adjustment element is anisotropic.Le problème décrit par la présente invention consiste à effectuer un multiplexage d'une lumière d'éclairage blanche et d'une lumière à bande étroite en utilisant efficacement la lumière par égalisation des angles d'émission des deux types de lumière tout en évitant une augmentation des coûts de production. La solution selon l'invention porte sur un dispositif source de lumière pourvu : d'une source de lumière d'éclairage blanche destinée à émettre de la lumière d'éclairage blanche ； d'une ou plusieurs sources de lumière à bande étroite destinées à émettre de la lumièr
