A flexible printed circuit (FPC) board includes a flexible substrate, an electric terminal portion, and a reinforcing structure. The electric terminal portion is disposed on a bottom surface of the flexible substrate and is suitable to be inserted into an electrical connector to electrically connect therewith. The reinforcing structure is disposed on a top surface of the flexible substrate and located just above the electric terminal portion. The reinforcing portion includes a stiffener plate bonded to the top surface of the flexible substrate and a pad bonded to a top surface of the stiffener plate. The pad is shorter than the stiffener plate.