A disk is placed into a disk drive device to be held therein. Then, a laser pickup is moved to the inner edge of the disk in step S1, various servos are automatically adjusted in step S2, TOC information of the disk is read in step S3, and a DBAL adjustment is performed in step S4. Here, the DBAL adjustment refers to an adjustment of a balance of a slice value for data. It is then determined whether or not the disk is recorded with information in multisession in step S5. If the disk is recorded in multisession, the DBAL adjustment for the session proceeds to a DBAL adjustment for a subsequent session in step S7. In other words, if the disk is a multisession disk, the DBAL adjustment is performed for each session.