A swiveling work machine includes: a swivel deck; an engine disposed rearward of the swivel deck; a suction type radiator disposed rearward of the swivel deck; a bonnet covering the engine and the radiator and forming an engine room; a cabin disposed frontward of the engine room; a partition wall standing on the swivel deck between the cabin and the engine room and forming a front portion of the bonnet; an air conditioner main body disposed frontward of the partition wall and in a lower portion of the cabin; an ambient air inlet for supplying ambient air to the air conditioner main body, the ambient air inlet being formed in a portion of the partition wall facing a radiator suction space; and a filter provided in the ambient air inlet.