Abstract: A circuit board for direct dissipation of heat energy from the installed electronic devices to facilitate the fabrication of a light-weight design of electronic product is disclosed to include a heat sink, a first insulating layer and a circuit layout. The heat sink has a working fluid contained in an enclosed chamber inside an envelope and a wick layer fixedly attached to the inner surface of the enclosed chamber for absorbing the working fluid. The first insulating layer is covered on the envelope of the heat sink. The circuit layout is arranged on a surface of the first insulating layer opposite to the envelope of the heat sink.