A hard disk drive (HDD) with an efficient connection between a flexible printed circuit and an actuator arm. The structure includes a flexible printed circuit having the flexible printed circuit and a stiffener for supporting the flexible printed circuit, and an actuator arm to which the flexible printed circuit is connected. An alignment hole, an alignment pin inserted into the alignment hole, a guide groove having one opened side, and a guide protrusion fitted into the guide groove are formed in the flexible printed circuit and the actuator arm, and the alignment hole and the alignment pin are fixed to each other through a soldering process.