There are provided a light source device and an image display apparatus. The light source device includes a first optical element that deflects a propagation direction of laser beams, a second optical element that separates laser beams, and a third optical element that defects the laser beams separated by the second optical element. The light source device further includes a light emitting unit that has one or more light emitting element emitting laser beams, an external resonator that reflects laser beams toward the first optical element and guides laser beams back to the light emitting unit, and a wavelength converting element that converts laser beams.