Embodiments suppress a fluttering phenomenon of a wiring structure portion for signal transmission between a head and an FPC. In one embodiment, an actuator has a support portion which accommodates a wiring structure portion. The wiring structure portion is provided at a rear end portion thereof with a wide tab, the tab having pads for connection with the FPC. The support portion has a convex wall portion formed so as to overlap a front end portion of the tab. An air current occurs at an end portion of a magnetic disk in the vertical direction. When the head accesses a track present on the inner periphery side of the magnetic disk, the tab approaches the disk end portion. Since the convex wall portion protects the tab against the air current, it is possible to suppress fluttering of the wiring structure portion and improve the head positioning accuracy.