To provide an ash disposal device simple in constitution so as to obtain stable action and moreover simple in maintenance control.

Collected ash 12 stored in a hopper 11 is fed into an ash transport pipe 14 by the opening action of an ash intake valve 13 and conveyed to a solid-gas separating filter 19 together with conveying air 16. In an ash disposal device of such constitution, the ash transport pipe 14 is provided with a powder flow switch 18 for detecting the presence of ash flow in the ash transport pipe 14, and opening/closing of the ash intake valve 13 is controlled by the powder flow switch 18.