A heat sink includes a tank and a plate covering on the tank and hermetically engaging with the tank. The tank includes a base for absorbing heat from heat-generating members and a first wick layer formed at an inner face of base. The plate has a second wick layer formed at an inner face thereof. A chamber is defined between the tank and the plate and contains working fluid therein. An artery mesh is located in the chamber between the tank and the plate. The artery mesh is in porosity communication with the first wick layer and the second wick layer.