To provide a cooling device with high liquid leakage detection accuracy which absorbs a cooling liquid leaking from a seal member to an external in a liquid leakage sensor.

The cooling device includes a first cooler 311 to which heat from a heating element Tr is transmitted, a second cooler 312 forming a cooling passage 313 in cooperation with the first cooler, the cooling liquid CL flowing in the cooling passage, the seal member 316 arranged on a junction part 315 of the first cooler and second cooler and sealing the cooling passage, and the liquid leakage sensor 319 detecting liquid leakage from the junction part. A gap part 318 is arranged between the seal member 316 of the junction part and the liquid leakage sensor 319 arranged outside the seal member.