A heat sink and its manufacturing method. The heat sink includes a base and plural heat pipes. The base has a first surface, plural parallel heated areas concavely formed on the first surface, a protrusion disposed between any two heated areas and protruding in a direction towards the first surface, and at least one notch formed on each protrusion. A first protrusion portion and a second protrusion portion are formed at the top of the protrusion and the top of notch respectively. The heat pipes are embedded into the heated areas respectively in the lengthwise direction, and the heat pipes at the notches of the protrusions are attached and in contact with each other. The notch of each heat pipe may be compressed and deformed, so that the heat pipes are in contact with each other.