To provide a building provided with a processing apparatus which can process an object to be processed within a processing gas and can be carried out of a processing chamber while the apparatus is not operated.

The building 1 has a processing chamber 2 within which removably installed is the processing apparatus M1 for processing, such as working the object in a processing gas. The processing chamber 2 is provided with a gas exchanging apparatus M2 which can reversibly exchange air contained in the processing chamber and breathed by one or more persons with the processing gas, so that the object can be processed in the processing gas contained in the chamber.