In an electronic apparatus having a liquid cooling system, and enabling optimal cooling characteristic for capacity with the aid of a radiator, which can be disposed or located fitting in a narrow space within a housing thereof, wherein a CPU (200) in need of cooling is installed within the housing (100), and the liquid cooling system for cooling the CPU comprises a cooling jacket (50) and a radiator (60)therein, wherein the radiator has a pair of headers (62) and (62), being constructed with disposing a large number of metal thin tubes (61,61...) there between, aligned in parallel to each other, and an outer configuration thereof can be changed easily and freely, and therefore it can be positioned even in the narrow space. Further, a cooling fan (64) or (66) for cooling the radiator (60) may be disposed therein, and in that case it is also possible to maintain a position for setting up a motor (65) or (67) for rotationally driving the fan, included therein.