To supply cheap coldness and hotness to a cultivation facility by combining natural water and a heat pump, facilitating installation, and efficiently using heat energy.SOLUTION: An air conditioner for a cultivation facility includes: heat release means 63, 65 arranged in the cultivation facility； a heat medium tank 200； a heat medium circulation circuit 210 supplying heat to the heat release means by a heat medium stored in the heat medium tank 200； a ground water circulation circuit 293 circulating ground water into a first heat exchanger 281 and a second heat exchanger 291: a heat medium going passage 283 and return passage 285 for ground water, circulating the heat medium in the heat medium tank 200 to the first heat exchanger 281； a heat medium circuit 341 for a heat pump, circulating the heat medium in the heat medium tank 200 via a heat pump 330； and a heat pump external circuit 351 circulating an external heat medium between the heat pump 330 and the second heat exchanger 291. The heat medium circulation circuit 210 is connected to the upper part and lower part of the heat medium tank 200 by a transmission circuit upper pipe 211 and a transmission circuit lower pipe 212.SELECTED DRAWING: Figure 8【課題】天然水、ヒートポンプ、等を組み合わせ、設置が容易であり、熱エネルギーを効率良く利用して安価な冷熱や温熱を栽培用施設に供給する。【解決手段】栽培施設に配置された放熱手段６３、６５と、熱媒槽２００と、該熱媒槽２００に蓄えた熱媒により放熱手段に熱を供給する熱媒循環回路２１０と、第１熱交換器２８１及び第２熱交換器２９１に地下水を循環させる地下水循環回路２９３と、第１熱交換器２８１に熱媒槽２００の熱媒を循環させる地下水用熱媒往路２８３及び復路２８５と、熱媒槽２００の熱媒をヒートポンプ３３０を介して循環させるヒートポンプ用熱媒回路３４１と、ヒートポンプ３３０と第２熱交換器２９１との間で外部熱媒を循環させるヒートポンプ外部回路３５１と、を有し、熱媒循環回路２１０は、送出回路上部管２１１と送出回路下部管２１２とで熱媒槽２００の上部と下部とに接続される栽培施設用冷暖房装置とする。【選択図】図８
