To provide a resin nozzle, which can be replaced separately with a sealability of a joint secured between a resin nozzle body and the resin nozzle on the front end of the nozzle body, reduces costs, and enables the low-cost manufacture of nozzles having different diameters.

A socket 35 is formed at the front end side of a through passage 34 of the nozzle body 31. A tapered entrance sealing part 36, whose diameter gradually widens toward the outside of the socket 35, is formed on the inner periphery of the opening end of the socket 35, and at least one inner sealing part 38 is formed to be deeper inside the through passage 34 than the entrance sealing part 36 is. A circular sealing part 43 is formed integrally on the outer periphery of the base end of the nozzle 33. The circular sealing part 43 has a bulged part 45, which comes in close contact with the entrance sealing part 36 when pressed by an inside facing collar 42 of a union nut 32 as the nut 32, which is fitted on the outside of the nozzle 33, is tightened on a male screw 37 of the socket 35, and a fitting projection 47, which comes in close contact with the inner sealing part 38 when pressed by the inside facing collar 42.