The present invention relates to a method for producing a tungsten oxide photocatalyst having titanium oxide and copper ion supported thereon, comprising dissolving urea in a solution in which copper-ion supporting tungsten oxide particles are uniformly dispersed in a titanium oxide sol, thermally decomposing the urea to thereby allow the titanium oxide to precipitate on the surface of copper ion-supporting tungsten oxide and to be supported thereon; and a tungsten oxide photocatalyst modified by both titanium oxide and copper ion obtained by the method, wherein the rate of change of diffuse reflectivity (at wavelength of 700 nm) is less than 3% before and after the irradiation of ultraviolet and the titanium oxide is supported on the tungsten oxide in an island shape of 1 to 100 nm in size. The tungsten oxide photocatalyst having titanium oxide and copper ion supported thereon of the present invention exhibits high catalyst activity under visible light irradiation.