To provide a clean bench that can quickly annunciate an abnormal situation on alarm action by a control device when a cleanness sensor detects lower cleanness in a working space than a specified value.

The clean bench 1 is equipped with the working space 6 having an opening 4A for inserting fingers therethrough at the front, a blower 11 to supply the working space 6 with clean air through a high-performance filter 9 for supply air, a channel 7 through which air is suctioned from the working space 6 by the blower 11 and a discharge channel 14 located on the downstream side of the blower 11 through which air is discharged outside via a high-performance filter 19 for exhaust air. The clean bench is also equipped with the control device 24 to control operation of the blower 11 and the cleanness sensor 30 to measure air cleanness in the working space 6.