An object of the present invention is to provide an infrared-shielding nanoparticle dispersion that has a property whereby visible light is adequately transmitted, and light in the near-infrared region is adequately shielded; an infrared-shielding body manufactured using the infrared-shielding nanoparticle dispersion; a method for manufacturing infrared-shielding nanoparticles that are used in the infrared-shielding nanoparticle dispersion; and infrared-shielding nanoparticles manufactured using the method for manufacturing infrared-shielding nanoparticles. The present invention is a method for manufacturing infrared-shielding nanoparticle dispersion obtained by dispersing infrared-shielding nanoparticles in a medium, an infrared-shielding body manufactured by using the infrared-shielding nanoparticle dispersion, and infrared-shielding nanoparticles used in the infrared-shielding nanoparticle dispersion, wherein the infrared-shielding nanoparticles include a substance expressed by the general formula MXAYW(1-Y)O3 (where M is one or more elements selected from H, He, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0<X≦1.2; 0<Y≦1).