PURPOSE: To completely remove harmful gas component in an exhaust cleaning mechanism having a wet washing column with a mist separator and an exhaust fan sucking exhaust washed in the column by installing an ion exchanger in the rear of the mist separator.

CONSTITUTION: In an exhaust cleaning apparatus which is installed to semiconductor manufacturing equipment, etc., exhaust containing harmful components which is sucked from the inlet 4 of a wet washing column 1 by a fan 2 attached on the outlet side of the column 1, after being washed by spraying circulating washing water 8, is discharged into the air through a mist separator 10. An ion exchanger 15 which also functions as a sound deadner for the fan is placed in a duct line of the exhaust passed through the mist separator 10. The ion exchanger is formed into more than one honeycomb board which is composed of laminated layers of the ion exchanger having a lot of holes to remove harmful gas components.