Optical recording medium capable of assuring sufficient levels of signals required for reading/writing data, and stamper for manufacture of the same

A stamper for use to manufacture an optical recording medium having a writable area in which grooves are formed along recording tracks and a read-only area in which pits are formed along the recording tracks, comprising:

• a stamper writable area in which stamper grooves are formed along stamper recording tracks and a stamper read-only area in which stamper pits are formed along the stamper recording tracks, wherein:
• where the refractive index of the optical recording medium provided extending from a light-incident surface to a surface in which the grooves and pits are formed is n and the wavelength of a light used for data write and read the optical recording medium is λ, the stamper grooves, and stamper pits each have a depth within a range of λ/7.5 n to λ/6.0 n;
• where the width of each of the stamper grooves formed in the stamper writable area is Wg and the pitch between the stamper recording tracks in the stamper writable area is Tp1, Wg/Tp1 is within a range of 18.4 to 31.1%;
• on the assumption that the width of each of the stamper pits formed in the stamper read-only area is Wp and the stamper pitch between the stamper recording tracks in the read-only only area is Tp2, Wp/Tp2 is within a range of 35.7 to 44.3%;
• and
• the stamper writable area has two stamper grooves formed double-spirally therein, at least one of the two stamper grooves is at least partially wobbled, and where the amplitude of the wobbling stamper groove is A, A/Tp1 is within a range of ±1.68 to ±2.53%.