Anti-mosquito net system with a pleated net moving along a top and bottom fixed horizontal guides, with a fixed side guide, sliding case, fixed retention case, panel of pleated net which has at its edges an axis with fastening buttons (11a-11f) and an axis with buttons for the passage (13a-13f) of the ropes, and ropes that run across the net horizontally in two groups, the bottom and the top, and are directed respectively as a bundle towards the top horizontal guide and as a bundle towards the bottom horizontal guide; it is characterized by the fact that it comprises: a) at least one intermediary sliding case which moves between the retention case and the side sliding case and parallel to them and which has on its top and bottom end an end component (17 and 27), with an opening with holes, a pulley (16, 26) and slottings on both of its sides for fastening two panels of net (7a and 7b), b) two panels of pleated net (7a and 7b) on each side of the intermediary sliding case, fastened on the top and bottom end components (17 and 27), in which also the second panel of net has on one edge of its net an axis with top buttons (18f, 18e, 18d) for the passing of the ropes (1, 2, 3) and bottom buttons (18c, 18b, 18a) for the passing of the ropes (4, 5, 6) respectively and on the other edge of the net an axis with buttons for the passage (37f-37a) of ropes, and also by the fact that on the one hand, the ropes (1, 2, 3) of the bundle of the bottom group run around the pulley of the top end component of the intermediary sliding case, afterwards they descend and through the top buttons of fastening (18f, 18e, 18d) respectively they run horizontally across the second panel of net, first the rope that exits through the bottom button of the first panel of net enters through the uppermost button of the second panel of net, then the rope which exits through the next towards the top button of the first net enters through the next towards the bottom button of the second panel of net and the rope that exits through the after next towards the top button of the first panel enters through the after next towards the bottom button of the second, on the other hand, the ropes (6, 5, 4) of the bundle of the top group run around the pulley of the bottom end component of the intermediary sliding case, afterwards they ascend and through the bottom buttons of fastening (18a, 18b, 18c) respectively, they run horizontally across the second panel of net, in the sequence, the rope that exits through the uppermost button of the first panel of net enters through the lowest button of the second panel of net, then the rope that exits through the next towards the bottom button of the first panel enters through the next towards the top button of the second panel and the rope that exits through the after next towards the bottom button of the first panel enters through the after next towards the top button of the second panel. a) at least one intermediary sliding case which moves between the retention case and the side sliding case and parallel to them and which has on its top and bottom end an end component (17 and 27), with an opening with holes, a pulley (16, 26) and slottings on both of its sides for fastening two panels of net (7a and 7b), b) two panels of pleated net (7a and 7b) on each side of the intermediary sliding case, fastened on the top and bottom end components (17 and 27), in which also the second panel of net has on one edge of its net an axis with top buttons (18f, 18e, 18d) for the passing of the ropes (1, 2, 3) and bottom buttons (18c, 18b, 18a) for the passing of the ropes (4, 5, 6) respectively and on the other edge of the net an axis with buttons for the passage (37f-37a) of ropes,