An air purifying operation is performed with a consideration for an influence of a purifying material on a person, and user's comfort and efficiency of the air purifying operation are both achieved. An air purifier includes a casing, an inlet, outlets, blowers, a decontamination unit, air ducts, movable louvers, a horizontal rotation mechanism, an ozone generation mechanism, human detection means, a control unit, or the like. The control unit detects whether or not there is a person in a room by the human detection means. Then, the control unit controls at least one of parameters including an ozone generation amount, a wind direction, an amount, and a speed of blown-out air based on the human detection result. Thus, if there is a person in the room, for example, a human avoiding operation, a human area operation, or the like can be performed. If there is no person, an indoor air purifying operation for uniformly purifying air throughout the room can be performed.
