To reduce floor shock sound through a solid propagation path and an air propagation path and further reduce propagation of radiation sound from a wall material to obtain an extremely high soundproof effect while regarding an entire building as a coupled system of sound and vibration.

A soundproof unit 6 which is vertically constituted of a plurality of layers formed of a plurality of partition materials 4B and an energy-absorbing member 5A such as an elastic rubber and provided with hermetical air chambers SA, SB partitioned having different sectional areas from each other is arranged. A ceiling material 2 is suspended from a ceiling base member through the soundproof unit 6.