Abstract: Provided is a magnetic recording medium substrate appropriate for a discrete medium and capable of fabricating a magnetic recording medium to/from which data can be written or read stably. Coaxial grooves (2) are formed on the surface of a resin substrate (1). The groove (2) has a width (T2) greater than a width (T1) of a track (3). Accordingly, when a magnetic layer is layered on the resin substrate (1), magnetic layers formed on the adjacent tracks (3) are not brought into contact and it is possible to prevent the problem that the magnetic layer is embedded in the groove (2). Thus, it is possible to physically separate the track (3) by the groove (2) and fabricate a magnetic recording medium to/from which data can written and read stably.