A heat sink includes a base having a first side in contact with a heat-generating electronic element and a second side opposed to the first side. Fins are formed on the second side of the base. A non-rectilinear air channel is formed between two adjacent fins, with a length of the non-rectilinear air channel being greater than a length of the base along an extending direction of the fins on the base. The heat sink may be provided to an outlet side of a heat-dissipating fan to form a cooler.