PROBLEM TO BE SOLVED: To improve the yield of a plant by enabling the plant to be locally cooled by simple means and lowering the temperature of a leaf which contributes to the growth of a flower cluster (fruit) affecting harvest in a high temperature period to activate a photosynthetic function.SOLUTION: A plant cultivation device S includes: a heat exchange member 10 which is attached to a stem 2 over a required length range of the stem 2 of a plant P which generates a flower cluster 3 between lamina joints 1a and through a base end 3a of a handle of at least one flower cluster 3 and exchanges heat with the stem 2； and cold heat applying means 20 that can apply cold heat of the temperature lower than the surface temperature of the stem 2 to the heat exchange means 10. The heat exchange member 10 is attached to the range which stretches, at least, from a lower part located below the base end 3a of the handle of the lowest flower cluster 3 to be a harvest target of the stem 2 to an upper part located above the base end 3a of the handle of the highest flower cluster 3 to be the harvest target. By using the plant cultivation device S, the plant is cultivated in a high temperature period while cooling the stem 2 by the cold heat applying means 20.【課題】 簡易な手段で植物を局所的に冷却できるようにするとともに、高温期において収穫に係る花房（果実）の生育に寄与する葉の温度を下げて光合成機能を活発化させ収量の向上を図る。【解決手段】 葉節１ａ間に花房３を生じる植物Ｐの茎２の所要長さ範囲に亘り且つ少なくとも何れか１つの花房３の柄の基端３ａを通って茎２に付帯され茎２との熱交換を行う熱交換部材１０と、熱交換部材１０に対して茎２の表面温度よりも低い温度の冷熱を付与可能な冷熱付与手段２０とを備えた植物の栽培装置Ｓを用い、熱交換部材１０を、茎２のうち、少なくとも、収穫対象となる最下位の花房３の柄の基端３ａより下に位置する下部位から、収穫対象となる最上位の花房３の柄の基端３ａより上に位置する上部位に亘る範囲に付帯させ、高温期に、冷熱付与手段２０により茎２を冷却しながら栽培する。【選択図】 図１
