To provide a reference axis positioning method for a satellite structure facilitating the positioning work and capable of being implemented by one worker.

Two points 5a, 5b are set in parallel with the reference axis of a satellite structure on a satellite structure face 5, and a main body 4a having a gauge mark 4c and a positioning jig 4 having a fitting section 4b to the satellite structure are fitted to two points 5a, 5b on the satellite structure face 5. A theodolite 3 is installed at the position where one gauge mark 4c of the positioning jig 4 can be collimated while the theodolite 3 is rotated around a prescribed axis El, the theodolite 3 is moved to the position where the other gauge mark 4c of the positioning jig 4 can be collimated while the theodolite 3 is moved and rotated around the prescribed axis El, these actions are repeated, and finally the theodolite 3 is positioned so that the gauge marks 4c can be collimated via the rotation of the theodolite 3 around the prescribed axis El only.