PROBLEM TO BE SOLVED: To allow, in association with a pipe fixing structure, standardization of pipe-like members the diameters of which are different from each other so as to facilitate component management, to improve efficiency of assembling a greenhouse stricture skeleton, and to reduce production costs.SOLUTION: A pipe fixing structure 10 is fixed to a pipe member 3 by radially holding the pipe member 3, the pipe fixing structure 10 comprising: a coupling support member 20 which has a pair of side plate parts 22 facing each other in a direction orthogonal to the direction of holding the pipe member 3 viewed from an axis of the pipe member 3, and which has a coupling support member 20 including a pair of skeleton material engaging parts 25 for supporting the pipe member 3 on one side of the holding direction； and a wedge member 30 which fixes the pipe member 3 by being inserted into an insertion hole 21 formed in the pair of the side plate parts 22 on the other side of the holding direction with respect to the pipe member 3, thereby holding and pressure-joining the pipe member 3 between the wedge member 30 and the skeleton material engaging part 25. In the pipe fixing structure, the position on a pipe side slide surface at which the wedge member 30 contacts the pipe member 3 in the holding direction is changed by an orientation of the wedge member 30 relative to the pipe member 3.
