A magneto-optical recording medium from which data is read by using a Kerr effect and which is capable of preventing signal imbalance caused from change in birefringence even in a system in which the amplitude of a reproduced signal is small and the spatial frequency of a shortest record signal train of the magneto-optical recording medium is 1.1 × NA/λ (line/m) or higher. The photoelastic coefficient of a substrate of the magneto-optical recording medium is 50 × 10 -13 cm 2 /dyne or smaller. The vertical birefringence of the substrate is 250 × 10 -6 or smaller, the coefficient of water absorption of the same is 0.2 wt% or lower and the thermal coefficient of expansion of the same is 6.5 × 10 -5 cm/cm· °C or lower.