To provide a multiplexer that makes it possible to achieve a reduction in size and that minimizes the influence of the expansion of laser light on a multiplexing unit. A multiplexer is provided with a plurality of waveguides, multiplexing units that are provided at an intermediate location within the waveguides, and laser light sources, wherein: the first multiplexing unit is arranged at a position that is closest to the laser light sources; and the laser light sources that have an optical axis at a position that is separated from the transmission axis of the visible light that is introduced into the first multiplexing unit are arranged so that the optical axis is inclined with respect to the transmission axis and the outer periphery of laser light that expands at a predetermined expansion angle passes in front of the first multiplexing unit.