A magnetic storage medium has a non-magnetic substrate and a recording layer. The recording layer comprises a non-magnetic matrix and crystal grains consisting of a ferromagnetic material. Each of the crystal grains dispersed in the recording layer is a columnar shaped grain which penetrates a suface of the recording layer and has height of 30 nm or less, and a mean value of grain sizes of the crystal grains in an internal direction of the recording layer is 15 nm or less. (Ku·V)/(kB·T) is not less than 60. A mean value Hk of anisotropic magnetic fields of the plurality of crystal grains is 20 kOe or less.