An electronic device includes a shell, an electronic component received in the shell, and a heat sink arranged between the electronic component and the shell. The heat sink includes a first heat spreader attaching to the electronic component, a second heat spreader spaced from the first heat spreader, and a plurality of fins between the first and second heat spreaders. Each fin includes a pair of contacting portions, a pair of bending portions and a connecting portion each of which being flat. The contacting portions are respectively connected to the two heat spreaders. The bending portions respectively extend from the contacting portions towards each other. Each bending portion forms a rear end adjacent to the other bending portion. The connecting portion interconnects the rear ends of the bending portions at opposite ends thereof.