PURPOSE: To accurately and surely fix a hub by curing an adhesive after the hub is pressure-fixed while rotating an optical disk.

CONSTITUTION: After the eccentricity of a disk substrate 1 is measured, the disk substrate is fixed so as to allow the center of the substrate coincides with the rotating center of a spindle motor 4. The adhesive is applied and while the disk substrate is rotated at a specified speed, the hub 3 is pressed with a specific force, then the rotation is stopped and the adhesive is cured with the irradiation of an ultraviolet light source 8. Thus the hub can accurately and surely be fixed.