To properly and efficiently clean an air filter of an air-conditioner according to working environment and operating conditions.

When the air filter 4 is cleaned by driving a filter driving motor 12 for a filter cleaner 11 of the air-conditioner, an operation integrating timer, a continuous operation integrating timer and an automatic cleaning operation integrating timer are started with the start of the operation to obtain various integrated times. The need or no need for cleaning the air filter is determined in accordance with a preset continuous operation integrated time or automatic cleaning operation integrated time. An automatic cleaning mode is executed after the operation of the air-conditioner is stopped in principle, however, if the air-conditioner is in operation when the operation integrated time reaches a prescribed value set in advance, the operation is forcibly stopped and the automatic cleaning mode is executed.