A heat sink includes a heat spreader for absorbing heat from a heat-generating source, a tank covering on the heat spreader and hermetically engaging with the heat spreader, a first wick layer formed on an inner face of the tank, a second wick layer formed on an inner face of the heat spreader, and a supporting member located between the tank and the heat spreader. A chamber is defined between the tank and the heat spreader and contains working fluid therein. The supporting member is arranged in a wave shape and supports the first wick layer and the second wick layer.