The oxide sintered body mainly consists of gallium, indium, and oxygen, and a content of the gallium is more than 65 at. % and less than 100 at. % with respect to all metallic elements, and the density of the sintered body is 5.0 g/cm.sup.3 or more. The oxide film is obtained using the oxide sintered body as a sputtering target, and the shortest wavelength of the light where the light transmittance of the film itself except the substrate becomes 50% is 320 nm or less. The transparent base material is obtained by forming the oxide film on one surface or both surfaces of a glass plate, a quartz plate, a resin plate or resin film where one surface or both surfaces are covered by a gas barrier film, or on one surface or both surfaces of a transparent plate selected from a resin plate or a resin film where the gas barrier film is inserted in the inside.