Abstract: The damper unit 10 is applicable to structures for seismic energy dissipation. The damper unit 10 comprises, a lower beam 11, an upper beam 12, a left column 21, a right column 22, axially yielding dampers 41, 42 functioning as an energy dissipating means, a left post-tensioned steel bar 31, and a right post-tensioned steel bar 32. The left and right post-tensioned steel bars 31 and 32 are inserted in the left and right columns 21 and 22, respectively. Upper ends of the steel bars 31 and 32 are connected with the upper beam 12. Lower ends of the steel bars 31 and 32 are connected with the lower beam 11. The columns 31 and 32 are semi-rigid connected with the upper beam 12 and the lower beam 11 by compressive forces generated from the steel bars 31 and 32. Therefore, the damper unit 10 possesses both self-centering and seismic energy dissipation characteristics.