Disclosed are a phosphor sheet capable for converting light from LEDs into white light, a white light source device including the phosphor sheet, and a display device including the white light source device. The disclosed phosphor sheet includes a phosphor layer containing at least a phosphor and a resin; and a pair of transparent substrates sandwiching the phosphor layer. The phosphor sheet comprises a coloring material having an absorption maximum wavelength of at least one of from 480 nm to 510 nm or from 570 nm to 620 nm. The coloring material is contained in the phosphor layer. The transparent substrates are adhered to both surfaces of the phosphor layer. the phosphor layer has a thickness of 20 μm to 200 μm. An indicator of the usage amount of the coloring material defined by the following formula is 0.003 to 0.028: (indicator of the usage amount of the coloring material)=((blending amount of the coloring material in the phosphor layer)/(blending amount of a resin in the phosphor layer))×(the thickness of the phosphor layer (μm)).