To provide a high performance wall damper at a low cost by fixing a wall type damper consisting of a plate viscous body vessel to girders of a plurality of upper and lower floors through lever members, and damping a vibration by use of its large interlayer deformation thereof.

This wall damper is formed of a viscous body vessel 4 and its mounting beam 7, a viscous resisting plate 6 and its mounting beam 8, and two lever members 9 as one unit. The wall damper is fixed to girders 2, 3 above and under a girder 15, skipping over the girder 15 for one floor, so that the interlayer deformation of a building extending to two upper and lower floors is utilized to generate the damping force of the damper. When an interlayer deformation is caused in the upper and lower floors by a horizontal force such as earthquake, the deformation corresponding to two floors in total is transmitted to the viscous resistant plate 6, and the displacement speed is also doubled to generate a double damping resistance. The damper is vertically continuously set, and shifted in position when juxtaposed. According to this, the number of dampers can be reduced to reduce cost.