To provide a rotary tub cleaning device capable of efficiently cleaning the rotary tub of an automatic washing machine.

The rotary tub cleaning device has a splash preventing container (1), a holding device (2) rotatably holding the rotary tub, a driving device (3) rotating the rotary tub holding section of the holding device (2), a jet nozzle (4) cleaning by jetting a cleaning liquid to the rotary tub, a nozzle moving device (5) moving the jet nozzle (4) and a cleaning liquid supply device delivering the cleaning liquid to the jet nozzle (4). The jet nozzle (4), when moved toward the bottom side of the rotary tub held, can change the jetting direction to the bottom. The nozzle moving device (5) has a guiding member (50) guiding the jet nozzle (4) to move, and a ball screw (51) provided along the guide member (50). The jet nozzle (4) is fixed to the nut member side of the ball screw (51) and can reciprocate along a screw shank member. The screw shank member can be always covered with cover members (55 and 55a).