A paint booth is provided with a purifier. The purifier includes a water tank, pump, water cord formation mechanism, sludge removal mechanism, exhaust mechanism, and barrier member. The water cord formation mechanism includes a water case located in an upper part of a spray chamber. A large number of nozzles are formed in a bottom wall of the water case. Each nozzle includes a tubular portion, the inside diameter of which is reduced downward from an inlet, and a circular outlet. Water falling in straight lines from the outlet forms a large number of parallel water cords. Paint mist is collected as air containing the paint mist contacts the water cords. An exhaust chamber is formed on the back side of the barrier member.