PROBLEM TO BE SOLVED: To provide a door device for a greenhouse such as a plastic greenhouse, using shared attachment metal fittings for attaching a reinforcing frame to rails regardless of being rails of a plurality of different types. SOLUTION: This door device includes a pair of rails 1 and 1 opposed to each other by confronting the ends with each other, a joint 2 covered on the outside of the rails 1 and 1 to connect the rails 1 and 1, a reinforcing frame 3 doubling as a gap cover, arranged along the rails 1 and 1 on the side lower part of the rails 1 and 1, and attachment metal fittings 4 for attaching the reinforcing frame 3 to the joint 2. The attachment metal fittings 4 are made of a vertical frame 4a, a horizontal frame 4b consecutively installed on the vertical frame 4a, and a hook 4c consecutively installed on the end of the horizontal frame 4b. The vertical frame 4a is coupled to one side wall 2b of the joint 2 while hanging the hook 4c to the edge of a mortise 3a. COPYRIGHT: (C)2011,JPO&INPIT