A device for depositing pasty material for fabricating a three-dimensional structure of large dimensions layer by layer, the device comprising: • at least three first supports (P1, P2, P3) at a distance from the ground and not in alignment supporting three respective first cable tensioning devices (M1, M2, M3); and • at least one second support kept at a distance from the ground and supporting a second tensioning device; and • a material feed pipe held suspended above the ground and suitable for being moved at least over the area between said three first supports; and • a deposition head at the end of said feed pipe suspended from said second tensioning device, preferably by a suspension cable; and • three cables referred to as "positioning" cables (7, 7-1, 7-2, 7-3) of respective lengths (L, L1, L2, L3), each connected at one end to said deposition head via a support guide, and each connected to a respective one of the three first tensioning devices (M1, M2, M3) at its other end, the three said positioning cables being suitable for being tensioned with different adjustable lengths by different actuation of the three first tensioning devices (M1, M2, M3) and of said second tensioning device, and being suitable by means of their adjustable lengths for defining an upside-down pyramid with a triangular top base, the bottom point of said upside-down pyramid defining a deposition point in three-dimensional space that is situated substantially at the deposition head at the bottom end of the feed pipe, said deposition point being suitable for being moved in the three dimensions XYZ of three-dimensional space between the three first supports (P1, P2, P3) by different actuation of at least one of the three said first tensioning devices (M1, M2, M3). • at least three first supports (P1, P2, P3) at a distance from the ground and not in alignment supporting three respective first cable tensioning devices (M1, M2, M3); and • at least one second support kept at a distance from the ground and supporting a second tensioning device; and • a material feed pipe held suspended above the ground and suitable for being moved at least over the area between said three first supports; and • a deposition head at the end of said feed pipe suspended from said second tensioning device, preferably by a suspension cable; and • three cables referred to as "positioning" cables (7, 7-1, 7-2, 7-3) of respective lengths (L, L1, L2, L3), each connected at one end to said deposition head via a support guide, and each connected to a respective one of the three first tensioning devices (M1, M2, M3) at its other end, the three said positioning cables being suitable for being tensioned with different adjustable lengths by different actuation of the three first tensioning devices (M1, M2, M3) and of said second tensioning device, and being suitable by means of their adjustable lengths for defining an upside-down pyramid with a triangular top base, the bottom point of said upside-down pyramid defining a deposition point in three-dimensional space that is situated substantially at the deposition head at the bottom end of the feed pipe, said deposition point being suitable for being moved in the three dimensions XYZ of three-dimensional space between the three first supports (P1, P2, P3) by different actuation of at least one of the three said first tensioning devices (M1, M2, M3).