PURPOSE: To prevent a recording layer from being deteriorated, burst errors from occurring and the surface of a glass base from being discolored, by a method wherein a soda-lime glass or the like is subjected to a low temperature type ion exchange treatment to replace Na+ on the surface of the glass by K+, and a thin strain layer is provided at a surface layer part.

CONSTITUTION: In a disk form transparent base for constituting an optical recording medium such as an optical-type information recording medium and an opto-magnetic recording medium, a disk form glass base having a ratio Na2O/ K2O (wt%) of larger than 1 is subjected to a low temperature type ion exchange treatment to set the ratio Na2O/K2O (wt%) in proximity to the surface of the base to 4×10-2W1. Further, the strain layer having a thickness of 5W100μm is provided at the surface layer part of the base.