Abstract: To detect whether barrel lids are fixed. A centrifugal barrel polishing machine (A) includes: a plurality of rotary tanks (50) that rotate planetarily; barrel lids (26) that are attachable to and detachable from the rotary tanks (50); and a plurality of clamp shafts (32) that are provided individually in the plurality of rotary tanks (50) so as to be rotatable integrally with the rotary tanks (50). Each of the clamp shafts (32) is displaceable between in a fixing form for fixing the barrel lid (26) to the rotary tank (50) and in a releasing form for releasing the fixation of the barrel lid (26). It is detected by a first detection means (40) whether the rotary tank (50) is positioned in a detection area (D) on a revolution path of the rotary tank (50), and it is detected by a second detection means (43) whether the clamp shaft (32) of the rotary tank (50) positioned in the detection area (D) is displaced to the fixing form.