An absorbing fine particle dispersion liquid containing liquid medium, absorbing fine particles dispersed in the medium, and a phosphite ester compound, wherein surfaces of the absorbing fine particles are coated with the phosphite ester compound, the absorbing fine particles are one or more kinds of oxide fine particles selected from tungsten oxide fine particles represented by a general formula WyOz in which the W is tungsten, the O is oxygen, and the y and the z satisfy 2.2≤z/y≤2.999, and composite tungsten oxide fine particles represented by a general formula MxWyOz in which the M is one or more elements selected from the group consisting of H, He, alkali metal, alkaline earth metal, rare earth element, 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, I, and Yb, the W is tungsten, the O is oxygen, and the x, the y, and the z satisfy 0.001≤x/y≤1 and 2.0≤z/y≤3, the phosphite ester compound is represented by the following structural formula, and an addition amount of the phosphite ester compound is 2000 parts by mass or more and 50000 parts by mass or less with respect to 100 parts by mass of the absorbing fine particles; where, in the structural formula, R1, R2, R4 and R5 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alicyclic group having 5 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms or an aromatic group, R3 is either a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and X is any one of a single bond or a sulfur atom or a divalent residue represented by structural formula, A is either an alkylene group having 2 to 8 carbon atoms or a divalent residue represented by structural formula, one of Y and Z is a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other one is either a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, in the structural formula, R6 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and in the structural formula, R7 is either a single bond or an alkylene group having 1 to 8 carbon atoms, and ∗ indicates that the residue is bonded to an oxygen atom side of the phosphite ester compound represented by the structural formula. surfaces of the absorbing fine particles are coated with the phosphite ester compound, the absorbing fine particles are one or more kinds of oxide fine particles selected from tungsten oxide fine particles represented by a general formula WyOz in which the W is tungsten, the O is oxygen, and the y and the z satisfy 2.2≤z/y≤2.999, and composite tungsten oxide fine particles represented by a general formula MxWyOz in which the M is one or more elements selected from the group consisting of H, He, alkali metal, alkaline earth metal, rare earth element, 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, I, and Yb, the W is tungsten, the O is oxygen, and the x, the y, and the z satisfy 0.001≤x/y≤1 and 2.0≤z/y≤3, the phosphite ester compound is represented by the following structural formula, and an addition amount of the phosphite ester compound is 2000 parts by mass or more and 50000 parts by mass or less with respect to 100 parts by mass of the absorbing fine particles; where, in the structural formula, R1, R2, R4 and R5 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alicyclic group having 5 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms or an aromatic group, R3 is either a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and X is any one of a single bond or a sulfur atom or a divalent residue represented by structural formula, A is either an alkylene group having 2 to 8 carbon atoms or a divalent residue represented by structural formula, one of Y and Z is a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other one is either a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, in the structural formula, R6 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and in the structural formula, R7 is either a single bond or an alkylene group having 1 to 8 carbon atoms, and ∗ indicates that the residue is bonded to an oxygen atom side of the phosphite ester compound represented by the structural formula.