Provided is an uninterruptible power supply apparatus that can properly adjust the capacity of cooling a heat radiation source. A housing for housing an uninterruptible power module is provided with a cooling fan for cooling the internal space of the housing. The housing is further formed with an opening. The opening formed in one housing and the opening formed in an adjacent housing for housing another uninterruptible power module are configured to face each other. Furthermore, each uninterruptible power module includes a fan control circuit for controlling the cooling fan. The fan control circuit controls the actuation and suspension of the cooling fan on the basis of a total load of the plurality of uninterruptible power modules.