A flexible printed circuit board and a bracket structure for the hard disk drive. The flexible printed circuit board includes a base layer, a circuit layer provided on the base layer, a cover layer provided on the circuit layer, and a filter layer interposed between the base layer and the circuit layer. Also, the bracket structure includes a flexible printed circuit board for driving an actuator, a bracket connected to the flexible printed circuit board, and a filter interposed between the flexible printed circuit board and the bracket. Thermal asperity caused by fine particles in the hard disk drive is prevented so that performance deterioration of the hard disk drive is prevented and reliability thereof is improved.