The invention relates to an optical disk drive, and more particularly, to a holder for disk drives having an improved chuck structure for seating a disk. The holder of the invention, in use, is inserted into a central opening of a disk for detachably seating the disk, and comprises: a circular hub projected upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion of the chuck.