A liquid cooling device includes a base, a housing and a heat exchanger. The base and the housing enclose a chamber which receives the heat exchanger therein. Inlet and outlet for liquid are provided at the housing. The heat exchanger includes stacked flakes. Each flake includes parallel and alternately arranged first and second strips each having a void defined therein. The flakes are stacked in a manner such that each first strip overlays and abuts against a corresponding second strip of an adjacent flake and that the void in each first strip and the void in the corresponding second strip of the adjacent flake are in fluid communication with each other to thereby form a channel between the inlet and the outlet.