PROBLEM TO BE SOLVED: To provide an opening/closing structure of a skylight window of a greenhouse in which, even in the case of providing the skylight window on inclined areas of both roofs of the greenhouse, the opening/closing arms can be installed for each beam, and there is no need to provide a support beam or a stationary beam for mounting the opening/closing means for opening/closing the skylight window.SOLUTION: An opening/closing structure 30 of skylight window opens/closes skylight windows 20 (20a,20b) provided for both roofs of a greenhouse 10, in which the opening/closing structure 30 comprises: drive shafts 34 (34a,34b) which are arranged on beams 12,120 parallelly installed in a width direction of the roof of the greenhouse 10 and severally move in a horizontal direction； and opening/closing arms 50 (50a,50b) attached to the drive shafts 34 (34a,34b) and open/close the skylight windows 20 (20a,20b), and is constituted so as to comprise the drive shaft 34a which opens/closes one skylight window 20a and the drive shaft 34b which opens/closes the other skylight window 20b which are provided on both roofs, on the beams 12,120.SELECTED DRAWING: Figure 6【課題】温室の両屋根の傾斜にそれぞれ天窓を設ける場合であっても、前記開閉アームを梁毎に設置でき、天窓を開閉する前記開閉手段を載置するための支持梁や固定梁を設ける必要がない温室の天窓の開閉構造を提供することを目的とする。【解決手段】温室１０の両屋根に設けられる天窓２０（２０ａ，２０ｂ）を開閉する天窓の開閉構造３０であって、前記開閉構造３０は、温室１０の屋根の幅方向に架設される梁１２，１２０の上に並行に配置され水平方向にそれぞれ移動する駆動軸３４（３４ａ，３４ｂ）と、前記駆動軸３４（３４ａ，３４ｂ）に取り付けられ前記天窓２０（２０ａ，２０ｂ）を開閉する開閉アーム５０（５０ａ，５０ｂ）とを備え、前記梁１２，１２０の上に両屋根に設けられる一の天窓２０ａを開閉する駆動軸３４ａと他の天窓２０ｂとを開閉する駆動軸３４ｂを備えるよう構成した。【選択図】 図６
