A heat-dissipating device includes a housing, a partitioning member, a finned structure, and a high thermal-conductivity strip. The housing defines an inner space, and has a top surface formed with a retaining groove, and an inlet and an outlet. The partitioning member is disposed in the inner space so as to divide the inner space into first and second compartments that are respectively connected to the inlet and the outlet. The finned structure includes a plurality of partitioning plates disposed in the first compartment so as to divide the first compartment into a plurality of partitioned sections that are connected to form a continuous meandering fluid path, and a plurality of heat-dissipating fins disposed in each of the partitioned sections. The conductive strip is secured in the retaining groove in the top surface of the housing and has a thermal conductivity higher than that of the housing.