NOVELTY - A surface treatment fluorescent substance comprises fluorescent material base containing alkaline-earth metal and silicon, and surface treatment layer containing alkaline-earth metal, silicon, and the specific element in groups 4-6 of periodic table. When a section of surface treatment layer is examined for thickness-direction distribution of elements with electron microscope and by energy dispersive X-ray elemental analysis, and the maximum peak for content of specific element is located to the surface than the maximum peak for content of silicon.    USE - Surface treatment fluorescent substance is used for fluorescent substance-containing resin composition, semiconductor light emitting device, light-emitting device for liquid crystal display element backlight, image display apparatus and illuminating device, and wavelength conversion composite complex for wavelength conversion sheet and photoelectric conversion apparatus (all claimed).    ADVANTAGE - The surface treatment fluorescent substance is efficiently and economically manufactured with improved moisture resistance, and excellent luminous efficiency and color tone.    DETAILED DESCRIPTION - A surface treatment fluorescent substance comprises fluorescent material base containing alkaline-earth metal and silicon, surface treatment layer containing alkaline-earth metal, silicon, and the specific element in groups 4-6 of periodic table. When a section of surface treatment layer is examined for thickness-direction distribution of elements with electron microscope and by energy dispersive X-ray elemental analysis, the maximum peak for content of specific element is located to the surface than the maximum peak for content of silicon, and silicon content in the fluorescent material base is less than the silicon content in the surface treatment layer. INDEPENDENT CLAIMS are included for the following:    (1) fluorescent substance-containing resin composition, which contains surface treatment fluorescent substance, epoxy resin and silicone resin;    (2) wavelength conversion composite complex, which is obtained dispersing surface treatment fluorescent substance to resin chosen from polyvinyl acetate, polyvinyl butyral, polyethylene, polypropylene, polymethylmethacrylate, polycarbonate and cyclic olefin copolymer;    (3) wavelength conversion sheet, which is obtained by forming wavelength conversion resin composite to a sheet form;    (4) photoelectric conversion apparatus, which has wavelength conversion composite complex or wavelength conversion sheet as structural component;    (5) light emitting device, which is obtained by providing fluorescent substance layer with light emitting diode chip, resin frame on light emitting diode chip and filling recessed portion on resin frame; and    (6) manufacture of surface treatment fluorescent substance, which involves forming surface treatment layer, providing solution containing complex ion containing specific element and fluorine for fluorescent material base, dispersing and contacting.