Abstract: A disc substrate of synthetic resin used for signal recording/reproduction by a head having a floating slider, in which the disc substrate is deburred to remove defects in appearance and is improved in strength and quality, and the manufacturing method and apparatus for the disc substrate. The manufacturing method includes a step of illuminating the laser light on at least the outer or inner rim portion of the disc substrate 2 of synthetic resin for transiently melting the illuminated portion. The manufacturing apparatus 1 includes a worktable 3 for supporting the disc substrate 2 in rotation, a positioning unit for positioning the disc substrate 2 at a pre-set position on the worktable 3 and a laser light source 4 for illuminating the laser light illuminating the laser light on the disc substrate 2 supported for rotation by the worktable 3. On the outer rim of the disc substrate 2 is formed a raised portion 26 not larger than 15 &mgr;m in height.

Abstract: A disc of synthetic resin used for signal recording/reproduction by a head having floating slider, in which the disc substrate is deburred to removed defects in appearance and is improved in strength and quality, and the manufacturing apparatus for the disc substrate. The manufacturing apparatus includes a worktable for supporting the disc substrate in rotation, a positioning unit for positioning the disc substrate at a pre-set position on the worktable and a laser light source for illuminating the laser light on the disc substrate supported for rotation by the worktable. On the outer rim of the disc substrate is formed a raised portion not larger than 15 &mgr;m in height. The raised portion has a thickness larger than that of the outermost portion of the disc substrate.