In an electronic apparatus, including personal computers, being called by a desktop type and a notebook type, as well as a server, etc., comprising a redundant cooling system, mounting a CPU 200 necessitating cooling in a housing 100, wherein a liquid cooling system for cooling the CPU comprises: a cooling jacket 50; a radiator 60; and two (2) sets of circulation pumps, and there are further provided check valves 91 and 92 and conduits 81, 82 . . . , so as to maintain circulation of the liquid coolant even when one of the two (2) sets of circulation pumps stops the function thereof, through the other circulation pump, thereby built up a redundant liquid cooling system.