To prevent a wall member from becoming bulky at the time of maintenance and transportation.

A wall member B1 for a partition is furnished with two pieces of a board 1 and a core part 2, an inner board 10 is stuck on an inner surface side of the board 1, and a connecting board 11 is stuck on one end side of the board 1 in the cross direction. Additionally, a fixed auxiliary board is provided on an outer surface of the board 1 in parallel. Furthermore, the core part 2 is constituted of a plural number of link boards 20, and both end parts of the link boards 20 in the cross direction are installed on the inner board 10 and the connecting board 11 free to revolve. Additionally, fixing members 5 are installed on the wall member B1 for the partition.