A heat dissipation device includes a canister filled with a phase-changeable working fluid, a housing hermetically fixed to a top of the canister and communicating with the canister, a fan located above a top of the housing and an impeller comprising a driving member received in the housing, an annular magnet accommodated in the hub and an axle coaxially connecting the driving member and the annular magnet together. The fan includes a plurality of windings fixed on an inner side thereof. When the working fluid is heated and vaporized to move through the driving member, the driving member is driven by the vaporized working fluid to rotate, whereby the annular magnet rotates within the windings to cause the windings to generate a current.