A connection box (16, 18) for optical fibres, comprising: - a chamber delimited between two opposite main walls (30, 88) of the box, the chamber having at least two distinct locations (E1, E2) following each other along a main axis of the support, adapted to receive turns of optical fibre so that the latter extend in plans different from each other; and - a support adapted to serve as a common bearing for the turns of each location, with a first part forming a base, single piece with a bottom of the box, and a second part forming a spacer, adapted to be removably added on the first part; said support comprising a cylindrical body adapted to define a minimum radius of curvature of at least one turn of optical fibre, box in which: - said locations (E1, E2) are axially delimited by respective tab-shaped elements (122a-c; 124a-c) carried by said second part forming a spacer, these tabs extending radially with respect to said main axis of the support and comprising: • first tabs (122a-c) delimiting a first one of said locations between the bottom of the box and the first tabs (122 a-c), and • second tabs (124a-c) delimiting a second one of said locations between the first tabs (122 a-c) and the second tabs (124a-c), - the first tabs (122a-c) moreover carry nib-shaped radial bearing elements (123a-c) that extend axially with respect to said main axis of the support, and the nib-shaped radial bearing elements (123a-c) defining a maximum radius of curvature for the second location, said box being characterized in that at least two of the tabs (122a-c) have maximum radial dimensions that are different from each other, and the lateral walls (28a-d) of the box define a maximum radius of curvature for the first location. - a chamber delimited between two opposite main walls (30, 88) of the box, the chamber having at least two distinct locations (E1, E2) following each other along a main axis of the support, adapted to receive turns of optical fibre so that the latter extend in plans different from each other; and - a support adapted to serve as a common bearing for the turns of each location, with a first part forming a base, single piece with a bottom of the box, and a second part forming a spacer, adapted to be removably added on the first part; said support comprising a cylindrical body adapted to define a minimum radius of curvature of at least one turn of optical fibre, - said locations (E1, E2) are axially delimited by respective tab-shaped elements (122a-c; 124a-c) carried by said second part forming a spacer, these tabs extending radially with respect to said main axis of the support and comprising: • first tabs (122a-c) delimiting a first one of said locations between the bottom of the box and the first tabs (122 a-c), and • second tabs (124a-c) delimiting a second one of said locations between the first tabs (122 a-c) and the second tabs (124a-c), • first tabs (122a-c) delimiting a first one of said locations between the bottom of the box and the first tabs (122 a-c), and • second tabs (124a-c) delimiting a second one of said locations between the first tabs (122 a-c) and the second tabs (124a-c), - the first tabs (122a-c) moreover carry nib-shaped radial bearing elements (123a-c) that extend axially with respect to said main axis of the support, and the nib-shaped radial bearing elements (123a-c) defining a maximum radius of curvature for the second location,