Device for joining or connecting two pipes (2, 2'), a first of which is provided with a male end portion and the second of which is provided with a female end portion, these two tubular end portions (3 and 4), having a circular section, being configured to be joined together by interlocking with the simultaneous creation of a mechanical connection and gas- and/or liquid-tightness, and with mutual alignment along an axial direction, these two end portions comprising respective first means (5, 5', 5") that cooperate with one another and are intended for the establishment, by translation and rotation, of a locked mechanical connection, and respective second means (6, 6') that cooperate with one another and are intended for the establishment of a sealed connection by compression of at least one seal against at least one contact surface in the locked state of the mechanical connection, and the male end portion having at least one locking pin or stud in one piece with its wall and protruding radially towards the outside, and the wall of the female end portion incorporating a circulation path that is able and intended to guide the or each pin, during the interlocking movement, as far as a locking receiving housing (5"), the joining device being characterized in that an elastically deformable part of the wall of the female end portion, which corresponds to a terminal segment of the guided circulation path, constitutes a member for immobilizing the pin in its receiving housing (5") in that the receiving housing (5") consists of an aperture in the wall of the female end portion, with a dimension in the axial direction greater than that of the pin or stud, and in that the guided circulation path comprises, from the free edge (4") of the female end portion, a first axially extending segment corresponding to a recess, to an indentation or to an outward deformation of the wall of this portion, and then a second, contiguous segment in the form of a cutout in said wall delimiting the elastically deformable wall part defining a wing, this cutout extending transversely with respect to the first segment and opening into the aperture (5") forming the locking receiving housing, and the sealing being realized regardless of the axial position of the pin in the receiving housing (5"). these two tubular end portions (3 and 4), having a circular section, being configured to be joined together by interlocking with the simultaneous creation of a mechanical connection and gas- and/or liquid-tightness, and with mutual alignment along an axial direction, these two end portions comprising respective first means (5, 5', 5") that cooperate with one another and are intended for the establishment, by translation and rotation, of a locked mechanical connection, and respective second means (6, 6') that cooperate with one another and are intended for the establishment of a sealed connection by compression of at least one seal against at least one contact surface in the locked state of the mechanical connection, and the male end portion having at least one locking pin or stud in one piece with its wall and protruding radially towards the outside, and the wall of the female end portion incorporating a circulation path that is able and intended to guide the or each pin, during the interlocking movement, as far as a locking receiving housing (5"), the joining device being characterized in that an elastically deformable part of the wall of the female end portion, which corresponds to a terminal segment of the guided circulation path, constitutes a member for immobilizing the pin in its receiving housing (5") in that the receiving housing (5") consists of an aperture in the wall of the female end portion, with a dimension in the axial direction greater than that of the pin or stud, and in that the guided circulation path comprises, from the free edge (4") of the female end portion, a first axially extending segment corresponding to a recess, to an indentation or to an outward deformation of the wall of this portion, and then a second, contiguous segment in the form of a cutout in said wall delimiting the elastically deformable wall part defining a wing, this cutout extending transversely with respect to the first segment and opening into the aperture (5") forming the locking receiving housing, and the sealing being realized regardless of the axial position of the pin in the receiving housing (5").