To provide a safety cabinet like a cabinet for bio-hazard measures minimizing infection when exchanging an HEPA filter using a bag without sterilizing, and an aftertreatment method after exchange of an air cleaning means.

This safety cabinet 1 is provided with an air feeding system feeding clean air to a work space 3 by an air blowing means 6 via an air cleaning means 5; an exhaust system discharging air to the outside of an apparatus via an air cleaning means 4 by an air discharging means from a circulation passage connected to the work space 3; a front face shutter 9 formed at the front face of the work space 3; taking-out ports of air cleaning devices 4, 5 to the outside; a cover 7 blocking the taking-out ports, a connection port 17 connecting the exhaust system to the outside; and a cap 18 blocking the connection port 17.