The present invention relates to an apparatus for cooling a power device of a power conditioning system. To this end, the present invention comprises: a power device; an evaporator butted to the power device; and a modularized condenser which is connected with the evaporator, placed on the power device, and equipped on the upper side of the power conditioning system. Accordingly, the present invention may easily secure a space, make it easy to install, and increase heat emission performance of the condenser so as to keep the power device at a low temperature, thereby enabling the system to be stably operated over a long period of time.