Aseptic junction device for a tube, comprising: - a tubular insert defining a channel and having a first end segment (20.1) provided with means for connecting it to the tube and a second end segment (20.2) which is intended to extend outside the tube; - an annular body comprising a first end segment (30.1) mounted on the second end segment of the insert, and also a second end segment (30.2) projecting axially from the second end segment of the insert to define therewith a housing; - an annular sealing element that is disposed in the housing between a front face of the second end segment of the insert and an internal step of the second segment of the annular body and that is deformable from a first state in which the sealing element delimits a fluid flow section and a second state in which the sealing element completely obstructs the channel, the sealing element being arranged to be brought from its first state to its second state under the effect of an axial compression; and - means (36, 63) for coupling to another junction device, the first end segment of the body being mounted on the insert so as to be movable axially between an axially projecting position of the insert and in which the sealing element is in its first state, and a flush position with the insert in which the sealing element is sufficiently axially compressed to be in its second state, characterised in that: - a maneuvering sleeve is rotatably mounted on the body between a connection position and a disconnection position, and is coupled to the insert so that a rotation of the sleeve from the connection position to the disconnection position leads an axial movement of the body from the projecting position to the flush position; and - the coupling means are arranged to allow decoupling of the junction device and the other junction device, only when the sleeve is in the disconnection position. - a tubular insert defining a channel and having a first end segment (20.1) provided with means for connecting it to the tube and a second end segment (20.2) which is intended to extend outside the tube; - an annular body comprising a first end segment (30.1) mounted on the second end segment of the insert, and also a second end segment (30.2) projecting axially from the second end segment of the insert to define therewith a housing; - an annular sealing element that is disposed in the housing between a front face of the second end segment of the insert and an internal step of the second segment of the annular body and that is deformable from a first state in which the sealing element delimits a fluid flow section and a second state in which the sealing element completely obstructs the channel, the sealing element being arranged to be brought from its first state to its second state under the effect of an axial compression; and - means (36, 63) for coupling to another junction device, the first end segment of the body being mounted on the insert so as to be movable axially between an axially projecting position of the insert and in which the sealing element is in its first state, and a flush position with the insert in which the sealing element is sufficiently axially compressed to be in its second state, characterised in that: - a maneuvering sleeve is rotatably mounted on the body between a connection position and a disconnection position, and is coupled to the insert so that a rotation of the sleeve from the connection position to the disconnection position leads an axial movement of the body from the projecting position to the flush position; and - the coupling means are arranged to allow decoupling of the junction device and the other junction device, only when the sleeve is in the disconnection position. - a maneuvering sleeve is rotatably mounted on the body between a connection position and a disconnection position, and is coupled to the insert so that a rotation of the sleeve from the connection position to the disconnection position leads an axial movement of the body from the projecting position to the flush position; and - the coupling means are arranged to allow decoupling of the junction device and the other junction device, only when the sleeve is in the disconnection position.