A fixing apparatus comprises a first fixing device and a second fixing device. The first fixing device has at least one first positioning groove adapted to position at least one first elongated member and fixes the at least one first elongated member. The second fixing device has at least one second positioning groove adapted to position at least one second elongated member and fixes the at least one second elongated member. Each first positioning groove is aligned with a corresponding second positioning groove so that the first elongated member fixed in the first positioning groove is axially aligned with the second elongated member fixed in the corresponding second positioning groove.