There is disclosed a vacuum cleaner including a dust separation section which separates air and dust flowing toward an intake port of a motor blower through a connection port of a cleaner main body. The dust separation section includes an air path forming member which performs a separation function. The forming member includes an introductory port, a derivative port, and an opening disposed between these. In the separation function, while dust-containing air flows toward the derivative port from the introductory port, a part of the air is sucked by the motor blower through the opening. Accordingly, the air is separated from the dust which goes straight in the air path forming member with inertia.