An air conditioner for a house cultivation facility that promotes the growth of plants in facility horticulture and increases the yield of agricultural products. In a house cultivation facility BH, a water supply pipe IN is connected to the entrance side of the electric heating water heaters H1 and H2, a discharge pipe OUT is connected to the exit side, and the gas-liquid indirect heat exchanger HE is connected to the discharge pipe. A hot water / cold water circulation device is configured through a cushion tank CT and a circulation pump P1 that are capable of supplying cold water. A medium temperature adjusting device is configured by connecting hot water in a circulating manner to a heating pipe HP arranged in the medium G in the house cultivation facility between the electric heating water heater and the cushion tank so as to circulate the gas-liquid indirect heat exchanger. The blower DCF is connected to the suction duct WD1 on the gas inlet side via the air volume adjusting damper SD, and the blower duct WD2 on the gas outlet side is connected to the house cultivation facility to constitute a hot air / cold air supply device. [Selection] Figure 1【課題】施設園芸における植物の生育を促進し、農産物の収穫量を増大させるべくしたハウス栽培施設の空調装置を提供する。【解決手段】ハウス栽培施設BHにおいて、電気加熱式温水器H1,H2の入側に給水管INを接続すると共に出側に排出管OUTを接続し、排出管に気液間接熱交換器HEと冷水供給可能にしたクッションタンクCTと循環ポンプP1を順次介して温水・冷水循環装置を構成する。電気加熱式温水器とクッションタンクと間にハウス栽培施設内の培地Gに配置した加温パイプHPに温水を循環可能に連通接続して培地温度調整装置を構成し、気液間接熱交換器の気体入側の吸引ダクトWD1に風量調節ダンパーSDを介して送風機DCFを接続すると共に気体出側の送風ダクトWD2をハウス栽培施設に連通接続して温風・冷風供給装置を構成する。【選択図】図1