An optical disc in which a physical address of each smallest recording unit and a recorded address increase or decrease on first and second recording layers, and a method of identifying the recording layers. Embodiments are provided for discs having first and second recording layers with a same or an opposite track spiral direction. Physical addresses of the smallest recording units and a recorded address are increased or decreased between an inner radius and an outer radius of a recording layer in a manner which enables a reproducing and/or a recording device to more rapidly reproduce and/or record data on the disc. A physical address of the smallest recording units on the first recording layer is made different from a physical address of the smallest recording units on the second recording layer.