PURPOSE: To make it easy to tension a nonmetal tension material in prestressed concrete and shorten a time required for the tensioning.

CONSTITUTION: When a plurality of tension materials 4 consisting of nonmetal material are simultaneously tensioned through an anchor head 1 so as to fix to a bearing pressure plate 5, they are connected to the anchor head 1 spirally by using a tension wire 6 consisting of a strand-like PC steel wire instead of a tension rod. Thereafter, the tension materials are tensioned by a jack unit 8 for PC steel material through a jack pedestal 7 equipped with the bearing pressure plate 5 and a temporary fixing plate 9. After the PC steel wire under the tension is temporarily fixed wedgewise by using the temporary fixing plate 9 at every stroke of the jack unit 8, it is tensioned again, and the anchor head 1 is fixed normally to the bearing pressure plate 5 at the time that a predetermined tension is given.