PURPOSE: To provide a resin for an optical high-density information recording medium, having a specific physical properties, and composed mainly of a copolymer obtained by the copolymerization of methyl methacrylate monomer, a specific ester monomer and a monoalkenylaromatic monomer at specific ratios.

CONSTITUTION: The objective resin for an optical high-density information recording medium, having a solution viscosity of 3W10cps as 10% methyl ethyl ketone solution at 25°C and a birefringence of ≤100nm, is prepared by copolymerizing (A) 40W70pts.wt. of methyl methacrylate monomer, (B) 5W20pts.wt. of an ester monomer of methacrylic acid and a 3W6C monohydric saturated aliphatic alcohol (e.g. propyl methacrylate) and (C) 25W40pts.wt. of a monoalkenylaromatic monomer (e.g. styrene). The information recording meduim can be obtained by applying microscopic unevenness to a surface of a plate made of said resin, and depositing a metallic film to the surface.