Abstract: A liquid-cooling device for an electronic component includes a heat exchanger, a fin set, a plurality of heat pipes and a fan fastened to a front side of the fin set. The heat exchanger defines a sealed chamber and has two inclined faces facing opposite to each other on a top thereof, and has heat exchanging members in the sealed chamber. An outlet and an inlet are respectively formed on the two inclined faces and in fluidic communication with the sealed chamber. The fin set includes spaced fins laminated together. Each heat pipe includes a semicircular evaporating portion embedded in a bottom surface of the heat exchanger and a round condensing portion extending upwardly and received in the fin set. The fan is located above the heat exchanger and behind the inlet and outlet of the heat exchanger.