Physical addresses of the recording areas provided on an optical disc are represented in a time-axis data format and in a binary data format. The physical address value gradually increases from the inner part of the disc to the outer part of the disc, while the formats remain in one-to-one correspondence over the recording areas. The distance the optical head must move to reach a target recording area can therefore be calculated easily independently of where on the disc the optical head is located, enabling the optical head to quickly access the target recording area.