Abstract: Provided are a system of highly clean rooms capable of continuously maintaining high cleanliness of air of class 1 or above and supplying enough oxygen inside the room for several persons to live in and a wall adapted to the structure of such a system. The system of highly clean rooms 10 is provided with a living space 6 and a space 5 between the roof and the ceiling as subspaces of an enclosed space formed by a room 1a. One of the lateral walls of the room 1a is constituted of a wall 9 with an internal space 7, which is a hollow wall. The internal space 7 and the living space 6 are in contact via an inner wall 9a of the wall 9, and a gas exchange membrane 26 is stretched in the inner wall 9a.