A heat dissipation device includes a heat dissipation member, a heat transfer member, and a reinforcing member. The heat transfer member has one side attached to the heat dissipation member, and two opposite lateral edges thereof are respectively provided with at least one connection portion and at least one through hole. The reinforcing member is connected to the other side of the heat transfer member, and two opposite lateral edges thereof are respectively formed with at least one mating connection portion for correspondingly connecting to the connection portion. The reinforcing member is provided at a central portion with an opening. With these arrangements, the heat transfer member can bear a larger locking force when the heat dissipation member is locked thereto, and is also prevented from deformation.