A heat sink (10) for removing heat from heat-generating devices includes a plurality of fins (12) interconnected together by a fastener (20) extending therethrough. Each fin comprises a main body (14) and a flange (16) bent from an edge of the body. The main body has a thickness and defines a through hole (141, 142, 143) therein. The fastener comprises a plurality of alternating bars (200) and positioned portions (212). Each positioned portion has a same thickness as the main body and is accommodated in the through hole. Each bar is sandwiched between two adjacent main bodies, for fixing the fins in position and preventing the fin from sliding along a length direction of the fastener. The bar has a width larger than a diameter of the through hole.