Abstract: A pair of small-sized air blowers or air blowing means, one being driven by means of an electric motor and the other being manually operated, are respectively connected to one end of two air inlet pipes each of which are selectively switched into operation by means of a three-way valve for providing flow and open feeding of air under pressure into a face covering type mask. An air inlet filter is mounted, as may be required, on the entrance side of the three-way valve. At least, one viewing window is provided on the front surface of the mask body. A transparent guard glass (and a colored, transparent light shielding glass for welding, as may be required) with suitable clearances for allowing the blowing-off of air therearound are oppositely fitted inside a viewing window. In addition, numerous small clearances are formed circumferentially between the inner side peripheral edge of the mask body and the face of a user to provide for air leak-off.