A pipe joint includes a joint body formed with a through hole therein along an axial direction, and having male threads and an extending shaft portion formed on one end side thereof; and a nut member formed with an insertion hole through which a tube member is inserted, and having female threads formed therein that screw-engage with the male threads. Annular projections are formed on an outer circumferential surface of the extending shaft portion, and the tube member, which is expanded in diameter, is gripped between the annular projections and an inner circumferential surface of the nut member.

A telescopic tube and methods of manufacturing it are disclosed. The manufacturing method includes placing a connecting ring around a tube body of the telescopic tube, then forming a connecting tube at one end of the tube body by injection molding so that the connecting ring is positioned between the connecting tube and the other end of the tube body. The method further includes coupling the connecting ring with the connecting tube.

A pipe joint includes a joint body formed with a through hole therein along an axial direction, and having male threads and an extending shaft portion formed on one end side thereof; and a nut member formed with an insertion hole through which a tube member is inserted, and having female threads formed therein that screw-engage with the male threads. Annular projections are formed on an outer circumferential surface of the extending shaft portion, and the tube member, which is expanded in diameter, is gripped between the annular projections and an inner circumferential surface of the nut member.

A connection structure includes: a first pipe member including a first fixing unit, a housing section, and an area closer to the second end side than the first fixing unit, the area being covered with an outer layer of the housing section; and a second pipe member including a two-stage structure including a first part, and a second part, a second fixing unit capable of being fixed to the first fixing unit, the second fixing unit being provided on an inner peripheral surface of the first part, and a positioning unit. The first pipe member is inserted into the second pipe member to determine positions with respect to each other by the positioning unit, the first and second fixing units are fixed to each other, and the outer layer is pressed and fixed to the first pipe member by the second part.