Provided are: a magnetic recording medium in which the
vertical orientation of a magnetic
recording layer is improved and the
recording density can be increased; and a magnetic recording / reproducing device provided with such a magnetic recording medium. A magnetic recording medium according to the present invention is provided with a non-magnetic substrate, an underlayer on the non-magnetic substrate, a seed layer on the underlayer, and a magnetic
recording layer on the seed layer, the seed layer containing two elements phase-separated from each other, the phase of one element [alpha] being mainly a columnar
crystal having an fcc structure, and the phase of the other element [alpha] being substantially a columnar
crystal having a fcc structure. The one element [alpha] mainly has an amorphous structure, and the other element [beta] mainly has an amorphous structure, and the underlayer includes, from the non-magnetic substrate side, a first underlayer, a second underlayer, and a third underlayer, the first underlayer mainly including any one of Ru, Cr, and Ni, the second underlayer mainly including the one element [alpha], and the third underlayer mainly including any one of Ru, Cr, and Mo.