Device for producing an airplane fuselage comprising a lamination mandrel defined by an external surface which defines a rotation solid with respect to a symmetry axis; said lamination mandrel is adapted to receive and support a band of impregnated synthetic material which is deposited and wound on the external surface forming a plurality of overlapping layers which are subjected to a polymerisation process under vacuum for forming a structural section of the airplane; the lamination mandrel comprises a plurality of sectors angularly spaced about the axis and mobile between: - an expanded lamination position in which the sectors have greater rectilinear edges parallel to the axis and arranged side by side and the external surfaces of the sectors opposite to the axis define together said external surface; and - a contracted disassembling position in which at least part of said sectors approaches the axis moving away from the trace of the surface to reduce the radial dimensions of the mandrel and allow the extraction of the mandrel itself from the structural section of the airplane; the side by side edges of different sectors are adapted to be arranged one on the other in a peripheral overlapping region, characterised in that a constraint system configured to operate with the sectors of the device for producing an airplane fuselage is provided; said constraint system is configured to be arranged between each sector and the sectors adjacent thereto; said constraint system comprising a first catch body borne by a first sector (12-A) and a second catch body borne by a second sector (12-B) adjacent to the first (12-A); the first and the second catch body being configured so that, when coupled to one another, a predetermined arrangement of the first sector (12-A) with respect to the second sector (12-B) adjacent thereto is obtained thus preventing any translation along two directions (x-y) which lie in an adjustment plane (PZ,) perpendicular to an axis RD which extends radially from said symmetry axis to the external surface; said first catch body comprises a cup-shaped body coaxial to the axis RD and open towards the second catch body; the first catch body further comprises three metal elements which are housed within the cup-shaped body and are defined by flat walls facing towards the axis RD and inclined with respect to this axis; said second catch body comprises an appendix provided with an end profiled as a spherical calotte adapted to abut in a single point P1, P2, P3 with a respective inclined flat wall; said three points P1, P2, P3 lie in said adjustment plane. - an expanded lamination position in which the sectors have greater rectilinear edges parallel to the axis and arranged side by side and the external surfaces of the sectors opposite to the axis define together said external surface; and - a contracted disassembling position in which at least part of said sectors approaches the axis moving away from the trace of the surface to reduce the radial dimensions of the mandrel and allow the extraction of the mandrel itself from the structural section of the airplane; the side by side edges of different sectors are adapted to be arranged one on the other in a peripheral overlapping region, characterised in that a constraint system configured to operate with the sectors of the device for producing an airplane fuselage is provided; said constraint system is configured to be arranged between each sector and the sectors adjacent thereto; said constraint system comprising a first catch body borne by a first sector (12-A) and a second catch body borne by a second sector (12-B) adjacent to the first (12-A); the first and the second catch body being configured so that, when coupled to one another, a predetermined arrangement of the first sector (12-A) with respect to the second sector (12-B) adjacent thereto is obtained thus preventing any translation along two directions (x-y) which lie in an adjustment plane (PZ,) perpendicular to an axis RD which extends radially from said symmetry axis to the external surface; said first catch body comprises a cup-shaped body coaxial to the axis RD and open towards the second catch body; the first catch body further comprises three metal elements which are housed within the cup-shaped body and are defined by flat walls facing towards the axis RD and inclined with respect to this axis; said second catch body comprises an appendix provided with an end profiled as a spherical calotte adapted to abut in a single point P1, P2, P3 with a respective inclined flat wall; said three points P1, P2, P3 lie in said adjustment plane.