A flexible printed circuit board includes a flexible sheet and a rigid substrate attached to the flexible printed circuit board. The flexible printed circuit board includes a first surface and an opposite second surface. A number of electrical connecting locations are defined on the first surface of the flexible printed circuit. The rigid substrate includes a third surface and an opposite fourth surface and is disposed on the flexible sheet with the fourth surface contacting the first surface of flexible sheet. The rigid substrate defines a number of through holes corresponding to the electrical connecting location to allow the electronic components to pass through.