A light guide prism for guiding image light from a display device to an observer's eye and displaying a virtual image of the display device in the observer's field of view includes at least four sides disposed to surround an optical path of image light incident from one end, a reflecting surface configured to reflect the image light guided by the at least four sides, and an emission surface configured to emit the image light reflected at the reflecting surface towards the observer's eye. At least one groove in a V-shape is formed on each of the at least four sides. As a result, a light guide prism that reduces stray light and ghost light occurring due to reflection at inner surfaces and an image display apparatus using this light guide prism can be provided.