A light source apparatus comprises a casing having a light emission window which is formed on a front side of the casing; a lamp provided in the casing; a light condensing reflection mirror which is provided in the casing and which has a reflection face therein for reflecting light emitted from the lamp towards the light emission window; a lamp position adjustment mechanism which holds the lamp and adjusts a position of the lamp in the casing; and a spatial separation wall, wherein a light source installation space is defined by the casing and the spatial separation wall structure member, and wherein the lamp position adjustment mechanism is disposed outside the light source installation space.