PROBLEM TO BE SOLVED: To prevent induction of excessive fatigue and peeling gilding in a folding part upon formation.SOLUTION: An introduction groove 1a for fixing a film F forming a plastic greenhouse G with a holding member S is formed into a table shape in its section with: a bottom part 11, both side wall parts 12 extending upper side with an arbitrary angle from both side end parts of the bottom part 11 and forming a space between their tip ends； and a curled part 13 arranged at the tip end of both side wall parts 12 and forming an opening 13a narrower than the space. The curled part 13 comprises: a straight part 13b extending to the bottom part 11 from the tip end of both side wall parts 12 with a right angle or approximately right angle； a curve part 13c extending from the straight part 13b and curving toward inside； and a fixing part 13d extending from the curve part 13c and extending to the tip end of both side wall parts 12 with its tip end. The opening 13a allows the film F and the holding member S placed on the film F to pass through so as to be introduced into the introduction groove 1a and removed from the introduction groove 1a. The fixing part 13d allows the holding member S introduced into the introduction groove 1a to contact to interposed film F so that the film F is prevented from removing from the introduction groove 1a via the opening 13a.【課題】 折り曲げ部分に過度の疲労や鍍金の剥れを誘発させずに形成可能にする。【解決手段】 ビニールハウスＧを形成するフィルムＦを止め部材Ｓで定着させる導入溝１ａが、底部１１と、底部１１の両側端部から任意の仰角で上方に延びて先端間に空きを形成する両側壁部１２と、両側壁部１２の先端に設けられて空きより幅狭の開口１３ａを形成するカール部１３とで断面台形状に形成され、カール部１３が両側壁部１２の先端から底部１１に対して直角あるいはほぼ直角に延びる直状部１３ｂと、直状部１３ｂに連続して内側に向けて折り曲げられる湾曲部１３ｃと、湾曲部１３ｃに連続して先端を両側壁部１２の先端に向けて延ばす係止部１３ｄとを備え、開口１３ａがフィルムＦおよびフィルムＦに重ねられる止め部材Ｓを通過させて導入溝１ａへの導入および導入溝１ａからの取り出しを許容し、係止部１３ｄが導入溝１ａに導入される止め部材ＳのフィルムＦ越しの当接を許容して導入溝１ａからの開口１３ａを通過する抜け出しを阻止する。【選択図】 図３
