A heat dissipation device removing heat from a memory module includes two conducting plate clipping the memory module and an elastic member. Each conducting plate includes a lower part and an upper part. The two lower parts of the two conducting plates abut against two opposite sides of the memory module, respectively. The two upper parts of the two conducting plates are pivotably connected together and located above the memory module. The elastic member is located between the two upper parts and urges the two lower parts towards the memory module. The upper part of each conducting plate is slantwise at an obtuse angle to the lower part to make the two upper parts of the two conducting plates splay upwardly.