A partition structure for absorbing an impact energy applied to the partition for petitioning a vehicle room includes a cover, a plurality of reinforcing member (wires) arranged with an interval in the vehicle width direction inside the cover, and a belt arranged behind the reinforcing member so as to intersect the reinforcing member. An installation structure for an installation part fixes an installation part to an installation target member by engaging and screwing the bolt with nut. A fixing seat is formed on a back surface of the installation target member integrally with the installation target member. A bolt is arranged in the fixing seat through the installation target member, and a holding part holding a nut on a back surface side of the seating face to prevent the nut from rotating.