PURPOSE: To provide a measuring method for measuring a position setting time required for moving an optical head to a desired target track on a host system screen without any auxiliary measuring device in an optical disk drive.

CONSTITUTION: A position setting time can be calculated by a position setting time measuring device based on a time obtained by subtracting a rotation delay time calculated from a disk format inputted by a user and the number of the rotation of a motor for rotating a disk or the like from an access time obtained by sensing a sector mark indicating the start of header information recorded in a disk track by rugged bits by a drive controller, and measuring a time until a host system is driven.