A partial drive-type backlight device comprising: a chassis (51, 151) having a bottom surface and side walls extending perpendicular to the bottom surface at a periphery of the bottom surface, an excitation light source that is formed from a plurality of light-emitting elements (10, 10B, 10M) and is partially drivable; a phosphor sheet (20, 120) disposed at a position separated from the excitation light source and containing a phosphor that converts at least part of a wavelength region of incident light from the excitation light source and releases emitted light in a wavelength region differing from the incident light; and a wavelength-selective reflection film (30, 130) that is disposed between the excitation light source and the phosphor sheet and that transmits at least part of light in the wavelength region of the incident light from the excitation light source and reflects at least part of light in the wavelength region of the emitted light from the phosphor sheet, wherein the plurality of light-emitting elements are provided in a grid shaped array on the bottom surface of the chassis, the phosphor sheet includes a phosphor layer containing the phosphor and a protective film for protecting the phosphor layer, the protective film being disposed on the side of the phosphor layer opposite to the wavelength selective reflection film, the phosphor layer and the wavelength-selective reflection film are directly joined such that the phosphor sheet and the wavelength-selective reflection film form an integrated sheet (25, 125) and, the side walls of the chassis are used as a spacer to position the integrated sheet in parallel to the bottom surface of the chassis. a chassis (51, 151) having a bottom surface and side walls extending perpendicular to the bottom surface at a periphery of the bottom surface, an excitation light source that is formed from a plurality of light-emitting elements (10, 10B, 10M) and is partially drivable; a phosphor sheet (20, 120) disposed at a position separated from the excitation light source and containing a phosphor that converts at least part of a wavelength region of incident light from the excitation light source and releases emitted light in a wavelength region differing from the incident light; and a wavelength-selective reflection film (30, 130) that is disposed between the excitation light source and the phosphor sheet and that transmits at least part of light in the wavelength region of the incident light from the excitation light source and reflects at least part of light in the wavelength region of the emitted light from the phosphor sheet, wherein the plurality of light-emitting elements are provided in a grid shaped array on the bottom surface of the chassis, the phosphor sheet includes a phosphor layer containing the phosphor and a protective film for protecting the phosphor layer, the protective film being disposed on the side of the phosphor layer opposite to the wavelength selective reflection film, the phosphor layer and the wavelength-selective reflection film are directly joined such that the phosphor sheet and the wavelength-selective reflection film form an integrated sheet (25, 125) and, the side walls of the chassis are used as a spacer to position the integrated sheet in parallel to the bottom surface of the chassis.