A remaining memory capacity of a memory is acquired in a predetermined cycle, and remaining memory capacity MR is stored in a remaining capacity database in association with an acquisition date. After that, it is determined whether or not a memory leak is present based on the remaining memory capacity and the acquisition date stored in the remaining capacity database. When it is determined that the memory leak possibly occurs, a usage limit period being a length of time to a point when a forced restart according to a usage limit threshold is performed is computed based on the remaining memory capacity and a memory decreasing rate. A restart schedule (and an all-stop period) is set within the usage limit period. On a date of the restart schedule, a management apparatus for managing an air-conditioning apparatus is restarted.