On an information recording medium, a data track pattern and a servo
pattern composed of a concave/convex pattern including a plurality of
convex parts are formed on at least one surface of a substrate and
respective concave parts in the concave/convex pattern are filled with
non-magnetic material. In the concave/convex pattern that constructs the
data track pattern, the respective convex parts are formed concentrically
or in a spiral. In the concave/convex pattern that constructs the servo
pattern, a unit convex part length along a direction of rotation of the
substrate is set so that a value produced by dividing the unit convex
part length by a distance from a center of the data track pattern
decreases from an inner periphery to an outer periphery.