An actuator with fewer components and a method of easily fabricating the actuator. The actuator includes first and second arm members stacked over each other, head gimbal assemblies respectively fixed to front ends of the pair of arm members, and a fastening mechanism fastening the pair of arm members. Each of the first and second arm members includes a core part coupled to the fastening mechanism and a blade part horizontally extending from the core part to have a different height from the core part and coupled to the head gimbal assembly. The blade part of the first arm member extends from the core part to have a greater height than the core part of the first arm member and the blade part of the second arm member extends from the core part to have a lower height than the core part of the second arm member so that a distance between the pair of blade parts of the pair of arm members can be greater than a width of a disk that is a data recording medium.