PURPOSE: To attain sound isolation and vibration isolation by providing, between a sleeper mounted on the joist part in the floor of the upper floor and a strap mounted on the cradling part of the ceiling of the lower floor, a member for mutually connecting the both by the shearing force of rubber.

CONSTITUTION: A sleeper 3 is mounted on the part of the joist 1 in the floor of the upper floor through a shock absorbing rubber 8. A strap 5 is mounted on the part of a cradling 4 in the ceiling of the lower floor. A member 7 having a rubber material 73 adhered between brackets 71, 72 is mounted on the strap 5 and the sleeper 3 through the brackets 71, 72. Further, a shock absorbing rubber 9 is interposed between a floor board 2 and the joist 1.