An information recording thin film (21) capable of changing an atomic arrangement upon exposure to a recording beam, formed on a substrate (19) directly or through a protective layer (20) composed of at least one of inorganic materials and organic materials, an average composition in the film thickness direction of the information-recording thin film being represented by the following general formula:
Sn x Sb y Te z Se α A β B γ C δ
wherein x, y, z, α, β, γ and δ are in ranges of 3 ≦ x ≦ 50, 10 ≦ y ≦ 70, 10 ≦ z+α ≦ 87, 0.1 ≦ z/α ≦ 10, 0 ≦ β ≦ 20, 0 ≦ γ ≦ 30 and 0 ≦ δ ≦ 30 in atomic percentage, A is at least one element of Tl, halogen atoms and alkali metals, B is at least one element of Au, Ag, Cu, Pd, Ta, W, Ir, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh and Ni, and C is at least one of other elements than Sn, Sb, Te, Se and those represented by A and B, or by the following general formula:
Sb x Te y A′ z B′ α C′ β D γ
wherein x y, z, α, β and γ are in ranges of 5 ≦ x ≦ 70, 10 ≦ y ≦ 85, 3 ≦ z ≦ 30, 0 ≦ α ≦ 20, 0 ≦ β ≦ 30, 0 ≦ γ ≦ 10, A′ is at least one element of Sn, Bi, Pb, Ga, Au and In, and B′ is at least one element of Tl, halogen atoms and alkali metals, C′ is at least one element of Ag, Cu, Pd, Ta, W, Ir, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh and Ni, and D is at least one of other elements than Sb, Te and those represented by A′, B′, and C′, gives an information-recording member having good recording and reproducing characteristics with a good stability for a long time and capable of a large number of information rewriting.