An actuator of a hard disk drive moves a magnetic head to record and reproduce data with respect to a disk to a predetermined position on the disk. The actuator includes a suspension supporting a slider where the magnetic head is mounted, and an arm included on a base plate of the hard disk drive to be capable of pivoting and having the suspension included at a leading end portion of the arm and a coil of a voice coil motor coupled to a rear end portion of the arm. The coil is coupled to the rear end portion of the arm by an outer mold formed to encompass an outer circumference of the coil, an inner mold formed inside the coil, and a connection mold connecting the outer mold and the inner mold is formed at least part of a surface of a non-effective portion of the coil except for an effective portion arranged to be perpendicular to a direction in which the arm pivots. Thus, a coupling force not only between the coil and the outer mold but also between the coil and the inner mold is increased so that a dynamic characteristic of the actuator is improved and a stable operation of the actuator is guaranteed.