A hard disk drive (1) includes a voice coil motor yoke (50), a base (60) to support the voice coil motor yoke, and formed of a material different from that of the voice coil motor yoke, and a thermal deformation prevention unit (70) which is formed of a material that is substantially the same as that of the voice coil motor yoke, provided between the voice coil motor yoke and the base, and thereby preventing mechanical deformation due to different thermal expansion coefficients between the voice coil motor yoke and the base.