To provide safety cabinet in which both elbows can be fixed without bringing the elbows into contact with the front suction port of a working table being a polluted area.

Arm supporting pedestals for supporting the arms of a worker are provided at the outside of a working area in the form independent from the working table. Thereby, the both elbows can be fixed without bringing the elbows into contact with the front suction port of the working table being the polluted area, and further it becomes possible to improve experiment operability and to maintain safety.