PROBLEM TO BE SOLVED: To provide an agricultural greenhouse heating system capable of efficiently heating the interior of an agricultural greenhouse and producible at a low cost with a simple structure.SOLUTION: An agricultural greenhouse heating system includes heating units 12 installed in an agricultural greenhouse 100, and a plurality of resin film-like ducts 14 juxtaposed with mutual spaces on the ground of the greenhouse interior S. The heating unit 12 includes a heater body 16 installed in a predetermined height position H from the ground GL in a position close to the greenhouse wall surface of the greenhouse interior, and sucking air into a case body from an air inlet 28 in the greenhouse interior-side side face of the case body to heat the air and exhausting the air to the outside from an outlet 30； a frame 18 for the heater body 16； and a flexible duct connection structure 22 including a plurality of flexible ducts 20 connected to the air outlet 30 of the heater body 16 and to the resin film-like ducts 14, and free to change a connection length from the outlet 30 to the resin film-like ducts 14 and the installed positions of the tips of the flexible ducts 20.【課題】農業用ハウスの室内を効率良く暖房できるとともに、構造が簡単で低コストで製造できる農業用ハウス暖房システムを提供する。【解決手段】農業用ハウス１００に設置される暖房ユニット１２と、ハウス室内Ｓの地面上で互いに離隔して並設される複数の樹脂製フィルム状ダクト１４と、を備え、暖房ユニット１２は、ハウス室内のハウス壁面に近接した位置で地面ＧＬから所定の高さ位置Ｈに設置され、ケース体のハウス室内側の側面の空気の入口２８からケース体内部に空気を吸込んで加温し出口３０から外へ出す暖房機本体１６と、暖房機本体１６を架台１８と、暖房機本体１６の空気の出口３０と樹脂製フィルム状ダクト１４に接続される複数の可撓ダクト２０を含み、該出口３０から樹脂製フィルム状ダクト１４までの接続長さ及び可撓ダクト２０の先端の設置位置を変更自在とする可撓ダクト接続構造２２と、を有する。【選択図】図１
