A rotation type working machine includes: an attachment mounted so as to be able to rotate with respect to a base body; a rotation mechanism which rotates the attachment; a control device which controls the rotation mechanism; and an entering object detection device which detects a position of an entering object entered into a work area, in which the control device controls a rotation operation of the attachment based on a first physical amount related to at least one of a current angular velocity of the attachment and a current moment of inertia of the attachment, and the position of the entering object detected by the entering object detection device.