Abstract: A light source device and an image display apparatus include a Blue Laser Diode (B-LD) light source unit, a dichroic mirror to reflect substantially collimated Blue (B) light from the B-LD light source unit, a lens to focus the B light reflected by the dichroic mirror, and a color wheel comprising a Green (G) fluorescent section which is excited by the collimated B light to emit and to reflect G light and a B mirror reflector to mirror-reflect the B light, wherein a center of a light flux of the B light reflected by the dichroic mirror is on other than an optical axis of the lens.