To ensure that a perpendicular magnetic recording medium having a granular magnetic recording layer made of CoCrPt alloy and Si oxide provides both high SNR and thermal stability. A substantially amorphous grain boundary layer of a magnetic recording layer made of CoCrPt alloy and Si oxide contains a ferromagnetic element in a concentration from 30at.% to 50at.% or more preferably from 35at.% to 47at.% so that intergrain exchange interaction takes place moderately. As a consequence, SNR of 18 dB or more and thermal stability of 3%/decade or less are achieved.