To provide an air conditioner enabling a safe and low-cost floor heating by forming a floor warming mat like one sheet and adapting the refrigerant feed rate required for this mat to the refrigerant feed power of a compressor.

An indoor unit 40 comprises an indoor heat exchanger 42 for heat exchanging between a coolant from an outdoor unit 30, floor warming mat 2 connected parallel to the heat exchanger 42 and means 41 for controlling the feed rate of the refrigerant to the mat 2. This mat 2 has basic mats coupled foldably at coupling, and contains refrigerant pipings for condensing the refrigerant fed across the basic mats, and these pipings are installed in semifixed or not fixed state near the couplings.