An optical recording medium includes a transmissive recording layer containing an oxide of a metal M.sub.A, an oxide of a metal M.sub.B, and an oxide of a metal M.sub.C. The metal M.sub.A is at least one kind selected from the group consisting of Mn and Ni. The metal M.sub.B is at least one kind selected from the group consisting of W and Mo. The metal Mc is Zr. An atomic ratio (M.sub.A/M.sub.B) of the metal M.sub.A to the metal M.sub.B is not less than 0.37 and not more than 1.31. The metal M.sub.C is contained in the transmissive recording layer at not less than 0.9 atomic % and not more than 27.5 atomic %.

An information recording medium according to the present disclosure is an information recording medium of a write-once-read-many type and records or reproduces information when irradiated with laser light. The information recording medium includes: a substrate; a plurality of information layers at least one information layer of which includes a recording film that is a W—O-based recording film comprising at least tungsten (W) and oxygen (O); and a dielectric film A in contact with the W—O-based recording film, the dielectric film A comprising at least 30 mol % tin oxide.

An information recording medium includes three or more information layers. The three or more information layers include a first information layer including a first dielectric film, a recording film, and a second dielectric film in this order. The first dielectric film contains an oxide of D1. The D1 represents at least one element selected from a first group consisting of Nb, Mo, Ta, W, Ti, Bi, and Ce. The recording film contains at least W, Cu, Mn, and oxygen and M. The M represents at least one element selected from a second group consisting of Nb, Mo, Ta, and Ti. The W, the Cu, the Mn, and the M except the oxygen in the recording film satisfy a following formula (1):

W.sub.xCu.sub.yMn.sub.zM.sub.100-x-y-z (atom %)(1) wherein x, y, and z satisfy 15x60, yz, 0<z40, and 60x+y+z98.

An information recording medium according to the present disclosure is an information recording medium of a write-once-read-many type and records or reproduces information when irradiated with laser light. The information recording medium includes: a substrate; a plurality of information layers at least one information layer of which includes a recording film that is a WO-based recording film comprising at least tungsten (W) and oxygen (O); and a dielectric film A in contact with the WO-based recording film, the dielectric film A comprising at least 30 mol % tin oxide.

An optical recording medium includes a plurality of information signal layers, and at least one of the plurality of information signal layers other than the farthest information signal layer from a light irradiation surface includes: a recording layer; a first dielectric layer provided on a side opposite to a light incident side of the recording layer; and a second dielectric layer provided on the light incident side of the recording layer. The first dielectric layer and the second dielectric layer include indium oxide and tin oxide, and the atomic concentration of tin in the first dielectric layer is higher than the atomic concentration of tin in the second dielectric layer.

An optical recording medium includes a plurality of information signal layers, and at least one of the plurality of information signal layers other than the farthest information signal layer from a light irradiation surface includes: a recording layer; a first dielectric layer provided on a side opposite to a light incident side of the recording layer; and a second dielectric layer provided on the light incident side of the recording layer. The first dielectric layer and the second dielectric layer include indium oxide and tin oxide, and the atomic concentration of tin in the first dielectric layer is higher than the atomic concentration of tin in the second dielectric layer.