To provide a direct operation type blower having a rotary shaft of an impeller connected to a shaft end of a motor and to be driven by a permanent magnet type motor having the controllable number of revolution, and having the equal selection with a belt drive method in spite of a remarkable reduction of the number of parts items and kinds of motor, having high efficiency over the whole area, and capable of lowering the loss of a piping system such as a loss of a damper.

In a blower with the structure that an impeller and a easing is provided and that a rotary shaft of the impeller 1 is directly connected to a rotary shaft of a motor, a permanent magnet type motor 3 is used as the motor, and the permanent magnet type motor 3 is driven by a driving device, and as the permanent magnet type motor 3, a permanent magnet type motor having several kinds of different basic frequency is used, and selection area is formed corresponding to plural different kinds of machines.