Optical information recording medium, optical information recording/reproduction method, and optical information recording/reproduction apparatus

An optical information recording medium comprising a recording layer, and a protective layer including at least first to mth layers (m≧2),

• wherein when i is an integer satisfying 1≦i≦m;
• a refractive index of the ith layer in the protective layer at a wavelength of 405 nm is ni;
• and a thickness of the ith layer is di, and when (a) a combined refractive index n of one layer which is substantially equivalent to the plurality of layers constituting the protective layer and substituted for the plurality of layers is specified as n=((n1d1+n2d2+ . . . +nmdm)/(d1/n1+d2/n2+ . . . +dm/nm))0.5;
• (b) a combined thickness d of said one layer is specified as d=((n1d1+n2d2+ . . . +nmdm)×(d1/n1+d2/n2+ . . . +dm/nm))0.5;
• and (c) an expression f(n):
• f(n)=−109.8n3+577.2n2−985.5n+648.6 is specified as a design criterion relating to the combined thickness of the protective layer,
• the refractive index ni of the ith layer and the combined refractive index n is equal to or larger than 1.45 and equal to or smaller than 1.65, and a difference d−f(n) between the combined thickness and the design criterion is equal to or larger than −10 μm and equal to or smaller than 10 μm.