To allow a balanced supply and exhaust to be obtained by a chamber body itself, and enable the supply, which is blown into a room, and the exhaust, which is exhausted to the outside of the room, to simultaneously make small when the opening degree of a front open port is made small.

In the chamber body 1 provided with a work space 11 within the inner portion thereof, an exhaust duct 27, which exhausts air in the work space 11 to the outside of the room, and a supply duct 29 provided with an exhaust port 39, which blows conditioned air from the outside into the inside of the room, are provided respectively. An open-close control valve for exhaust 31 is provided in the exhaust duct 27 and an open-close control valve for supply 35 is provided in the supply duct 29, respectively. The valve opening degree can be controlled simultaneously by interlocking the open-close control valve for exhaust 31 and the open-close control valve for supply 35 with the opening degree of an open-close door 15, which opens and closes the front open port 13 of the work space 11, and on the other hand, the valve opening degree is simultaneously made small when the opening degree of the open-close door 15 is small thereby saving energy.