Patent ID: 8059368

Claim:
A magnetic recording medium substrate comprising: a plurality of protruded portions formed on a substrate, each protruded portion being in a track shape and being made of the same material as the substrate; and depressed portions formed on the substrate, each depressed portion separating adjacent protruded portions and a minimum distance of each depressed portion in a track width direction being greater than zero, each protruded portion including a plurality of first portions and second portions for connecting the first portions adjacent thereto in a track longitudinal direction, and each second portion having a cross-sectional area in a track width direction that is smaller than a cross-sectional area in a track width direction of adjacent first portions, each of the adjacent first and second portions are continuously formed along the track longitudinal direction, wherein the cross-sectional area in the track width direction of each second portion continuously decreases as a distance from one of the two adjacent first portions increases until the cross-sectional area reaches the smallest value, and then continuously increases as a distance to the other first portion decreases.