PROBLEM TO BE SOLVED: To prevent occurrence of misreading of a BCA mark caused by a difference of reflectivity of a land face and a reflectivity of a groove face becoming 30% or more in an auxiliary information area.;SOLUTION: An optical information recording medium has: an annular substrate 11 in which a spiral groove 12 is formed in one of main faces; on the main face side, a light reflection layer 13 on the surface of which a groove 13b corresponding to the groove on the substrate is formed and reflects a laser beam; an optical recording layer 14; a protection layer 15; and a light transmission layer 17 in this order. Also, the medium is equipped with a main information area and an auxiliary information area at an inner circumference side from the main information area. Track pitch TrB of a groove of the auxiliary information area is 0.32 μm or less, and the depth D of this groove and half value width W of the groove satisfy a relation expressed by W≥2D+70. Thereby, occurrence of misreading of the BCA mark can be prevented, since the difference between the reflectivity of the land face and the reflectivity of a groove face in the auxiliary information area can be suppressed to less than 30%.;COPYRIGHT: (C)2008,JPO&INPIT
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