A manufacturing method of a heat conducting device includes following steps: providing a first plate, which includes a plate body and at least a heat conducting element, wherein the plate body has at least an inserting end disposed corresponding to the heat conducting element and defining a tube, and the heat conducting element is mounted at the tube; providing a second plate, which has a first opening end; disposing a first wick structure on an internal wall of the heat conducting element and a bottom surface of the plate body; disposing a second wick structure on an internal wall of the second plate; and connecting the plate body to the first opening end so as to connect the first plate and the second plate to form a chamber. Accordingly, the heat conducting device has a higher heat conducting efficiency.