A connector of the invention is one for connecting an end portion of liquid medication tube, blood tube, or tracheal tube to an end portion of an external circuit, including a male terminal portion 2, and a female terminal portion 3 which is capable of being conically coupled and which is made of a relatively rotatable internal barrel 5 and external barrel 6, in which protrusion strips 11 and grooves 12 as an engaging device are provided respectively on an outer circumferential surface of the internal barrel 5 and in an inner circumferential surface of the external barrel 6, the protrusion strips 11 and the grooves 12 being brought into contact with each other as a result of elastic deformation of the external barrel to make restraint of the rotation inside the connector possible. The invention can provide a rotating connector which is capable of being conically coupled and easily disconnected while having a rotation mechanism inside the connector.