Device for folding and unfolding hail protection nets in crop fields, consisting of rows of posts (1) in correspondence with the plantation rows, each row having a ridge cable (2) on which the protective netting (4) is mounted, locked-coil cables (6) actuated by vertical shaft pulleys (5) and a second lower ancillary cable (7). The nets (4) are actuated by means of deployment and retraction cables (9, 10) joined to attachment points distributed along the lateral edges thereof, wherein the deployment cables (9) extend towards the lower ancillary cable (7) of the adjacent row and return to their row to connect to the lower section of the locked-coil cable (6), and the retraction cables (10) are attached to the upper section of the locked-coil cable (6) of their row. The system is deployed or retracted in accordance with the direction of rotation of the pulleys (5, 13) that move the locked-coil cables (6), wherein said actuation may be centralised by means of second cables (14) attached to said locked-coil cables (6).
