A multilayer heat sink including a heat-receiving layer, a channel layer including cooling micropaths extending and directing a fluid in a direction orthogonal to a stacking direction, an orifice layer including jet orifices configured to jet the fluid into the cooling micropaths, and drain orifices configured to drain the fluid from the cooling micropaths, a header layer including a peripheral wall and a baffle, and a bottom layer, wherein the baffle includes parallel plates disposed parallel to each other, and end plates configured to alternately close an opening at an end and an opening at an opposite end of the parallel plates, and the orifice layer, the bottom layer, the baffle, and the peripheral wall define a supply channel to guide the fluid from a fluid inlet to the jet orifices and a drain channel to guide the fluid from the drain orifices to a fluid outlet.