To provide a house for protected horticulture which uses straight iron pipes that can easily be obtained for the framework and is easily assembled.

This house has a coupling member 10 which is formed by bending a double pipe, having a long and thin iron pipe 14 inserted into a short and thick pipe 12, while forming a grooved hollow parallel to the double pipe inside at the central part of the double pipe, a pentagonal iron plate piece 21 which has its peak part made arcuate and has a hole 23 in a key hole shape consisting of a round hole and a groove for implanting a channel-shaped wedge 28 at the center part and tow small holes 26 for inserting screws for band fixation at positions symmetrical about the hole 23 in the key hole shape, and a coupling member 20 consisting of the wedge 28 for fixing a pipe 3 to the iron plate piece 21. Then iron pipes 1 of a flank and iron pipes 2 of a roof are coupled by coupling members 10 to form an arch, and a depth-directional iron pipe 3 is inserted into the hole 23 in the key hole shape of the iron plate piece 21 and fixed with the channel shaped wedge 28.