A projection-type image display apparatus includes a light source unit that emits light, an image generating unit that generates image light according to an input video signal, a light-guide optical system that guides the light from the light source unit to the image generating unit, and a projection optical system that projects the image light generated by the image generating unit. The light source unit includes a light source that produces light, phosphor that is excited by the light from the light source, and a dichroic mirror that directs the light from the light source to the phosphor. The dichroic mirror is arranged with an incident angle of the light from the light source being 50° or more and 60° or less.