PURPOSE: To provide a light source device for a projector capable of concurrently miniaturizing a projector main body and increasing its intensity.

CONSTITUTION: A light source device for a projector is provided with multiple light source units 1 each having a light source 7, a light collecting device 8 collecting the outgoing light from the light source 7, a power source device for driving the light source 7, and a cooling device 9, primary side light guides 2 guiding the light sent from individual light source units 1 and collected by the light collecting devices 8 to a photo-coupler 3 common to part or all of the light source units 1, and a secondary side light guide 6 transmitting the synthesized light of multiple primary side light guides 2 synthesized by the light coupler 3.