PROBLEM TO BE SOLVED: To provide a curtain mechanism for a green house capable of reducing a gap produced in the gable surface of a green house and more increasing the airtightness, heat insulation properties, or the like in a green house by a simple constitution.SOLUTION: In addition to driving wire 10 for a ceiling plane covering part, driving wire 20 for sagging parts connected with the inner edge parts of the respective sagging parts 412, 422 of first and second curtain members 41, 42 is provided. A respective forward running part 21 and opposite running part 22 of the driving wire 20 for sagging parts include third and fourth junction pulley members 66d, 66e as stoppers provided at the positions passing over the terminal positions upon expansion of the respective ceiling plane covering parts 411, 412 of the first and second curtain members 41, 42 connected to a first guide member 31 and a second guide member 32 and deciding the positions of the terminal positions upon expansion of the inner edge parts of the respective sagging parts 412, 422 of the first and second curtain members 41, 42. In this way, parts of the inner edge sides of the respective sagging parts 412, 422 are mutually overlapped in the terminal positions upon expansion.
