A heat pipe assembly includes at least a flattened portion formed on the heat pipe. The internal surface of the heat pipe includes a wick structure attached thereon, and a mesh supporting member disposed therein. The wick structure is compressed on the internal surface of the heat pipe by using the mesh supporting member. The mesh supporting member includes a plurality of radially and axially arranged stripes. The radially and axially arranged stripes are orthogonally stacked, thereby forming mutually communicable working fluid channels in the flattened portion of the heat pipe.