An original master manufacturing method of rotating an original master at a constant linear velocity, moving in a plane the original master in a predetermined radial direction at a constant velocity which is provided with a predetermined amount of movement per round of the original master, deflecting the electron beam in the planar movement direction of the original master by a first deflection amount equal to the predetermined movement amount per round of the original master on the surface of the original master during exposure of the concentric circular data patterns corresponding to first through (n-1)-th rounds of each of the plurality of tracks, upon completion of the exposure of the concentric circular data patterns corresponding to the first through (n-1)-th rounds, deflecting the electron beam in a direction opposite to the planar movement direction of the original master by a second deflection amount equal to the predetermined distance on the surface of the original master, and upon completion of exposure of the concentric circular data pattern corresponding to an n-th round of each of the plurality of tracks, deflecting the electron beam in the direction opposite to the planar movement direction of the original master by a third deflection amount on the surface of the original master such that an irradiation position of the electron beam is located at an exposure start position on the concentric circle of a first round of an adjacent track.