A light source apparatus permits an angular range of illumination light to be changed, wherein the apparatus can be made thin. A related display apparatus permits a visible angular range to be changed using the light source apparatus. The display apparatus can be mounted in a terminal device, ahd an optical member and an optical unit can be incorporated in the light source apparatus. The light source apparatus is provided with a light guide plate with a conical sheet. Two light sources are provided on side surfaces of the light guide plate. Two inclined surfaces whose inclination angles to a light output surface differ from each other are formed at a light diffusion surface of the light guide plate. The conical sheet is provided with a flat plate portion on which a plurality of cones are formed. The cones protrude toward the light guide plate.