A heatsink assembly having a simple structure for coupling a heatsink and an electronic chip is provided with a heatsink which contacts an electronic chip mounted on a substrate and absorbs heat generated from the electronic chip; and a pressing member which is coupled to the substrate and comprises: a pressing cover for pressing the heatsink so that the heatsink can be secured to the electronic chip; and tension parts which extend from the pressing cover and exert a pressing force onto the pressing cover, when being coupled to the substrate.