According to one embodiment, an actuator assembly includes a head actuator including an actuator block having a first surface, a second surface intersecting the first surface, and a first groove provided on the second surface, and a suspension assembly supporting a magnetic head and a wiring board including a plate arranged on the first surface, a flexible printed circuit board provided on the plate, and an IC chip provided on the flexible printed circuit board, wherein the plate comprises a first engaging portion engaging with the first groove.