PROBLEM TO BE SOLVED: To improve a ventilating apparatus for a plastic greenhouse that ventilates the plastic greenhouse, arranging an open/close seat diagonally to serve as an eave.SOLUTION: The ventilating apparatus A for the plastic greenhouse is provided with the open/close sheet 4 installed opposing to an opening frame that forms an opening to the plastic greenhouse, a winding shaft 5 installed in a lower end of the open/close sheet 4, and a driving member K that rotationally drives the winding shaft 5, wherein the driving member K rotates the winding shaft 5 to wind up the open/close sheet 4 around the winding shaft 5 to open the opening. The ventilating apparatus also includes an arm 6 which is pivoted to the opening frame in a vertically freely rotatable manner to move a tip 62 close to or away from a lower frame 3, and has an insert hole 60 at the tip 62 so that the winding shaft 5 can be freely inserted thereto.
