A multi-chip module cooling device is provided which equally and efficiently reduces the rises in temperature of LSI chips, and which is superior in the productivity of multi-chip modules, such as their capability to be assembled and disassembled. A multi-chip module includes semiconductor devices and a sealing top plate for removing the heat generated by them. The sealing top plate has a number of parallel cooling channels and a number of cross grooves extending partially across the cooling channels. The cooling channels arc covered with a cooling channel cover, which is provided with turbulent promoters on an inner wall thereof. When the cooling channel cover is placed over the sealing top plate, the turbulent promoters engage with the cross grooves. The turbulent promoters are positioned midway between adjacent semiconductor devices.