PROBLEM TO BE SOLVED: To provide a medical appliance, a medical appliance assembly, a balloon device, and a method for treating urinary tract constriction for quickly delivering and positioning a medical member, and capable of improving detention property of the medical member.SOLUTION: A medical appliance 200 is used for delivering a medical member 300 to be located on a treatment part of an urinary tract, and comprises: a body part 220 having flexibility and extending in an axial direction； a balloon 210 having an expansion effective part 211 to which the medical member is attached, in which an expansion space part 218 to which a compressed medium flows, is formed between the balloon and an external face of the body part, and which can expand and deform and shrink and deform； a long guide member 230 disposed over the treatment part and outside of a living body, via the urinary tract； and an attachment part 260 for attaching detachably, a part of the guide member to a position between both ends in the axial direction of the body part. The body part can move in the urinary tract along a path where the guide member is disposed, in a state in which the guide member is attached to the attachment part.SELECTED DRAWING: Figure 2
