A rigid-flex circuit board includes a core substrate, a first adhesive layer, and a first outer conductive circuit layer. The core substrate includes a first and a second base layer, a first and a second conductive circuit layer respectively on the first and second base layer, and an insulating layer between the first and second base layer. The first and second conductive circuit layer are embedded in the insulating layer. The first adhesive layer is on the first base layer and defines a first opening which exposes the first opening. The first outer conductive circuit layer is on the first adhesive layer and defines an opening aligned with the first opening. A portion of the core substrate located within the first opening is defined as a flexible board section, and the portions of the core substrate located outside of the first opening are defined as a hard board section.