Lateral sliding roller insect screen comprising: a side box arranged vertically, configured to enclose coaxially therein moving means (9, 10) of the net of the insect screen; a vertical handle-bar configured to enclose coaxially therein a winding roller for the net and to slide in horizontal direction forwards and rearwards to the box; upper and lower closing means of the box and upper and lower closing means of the handle-bar; a screening net interposed between said box and said bar, said net being fastened to an end to the box and to the other one to said winding roller; a couple of guide means (6, 6'), respectively lower and upper, for the net, said guide means (6, 6') being fastened to an end to said closing means of the handle-bar and having the opposite end configured to be able to slide inside the box; said moving means (9, 10) are interposed between said upper and lower closing means of the box; said insect screen being characterized in that - said moving means of the net comprise a couple of gear wheels configured to be coaxially rigidly coupled to an innerly hollow cylindrical element interposed between said couple of gear wheels inside a hollow seat of the box, so that the upper gear wheel can interact with said upper guide means and the lower gear wheel can interact with said lower guide means, - said guide means (6, 6') are configured to interact mutually with said moving means (9, 10) so that upon an outer action on the handle-bar the rotation of at least a gear wheel causes a displacement of said upper guide means with equal pitch as the one of said lower guide means or vice versa. a side box arranged vertically, configured to enclose coaxially therein moving means (9, 10) of the net of the insect screen; a vertical handle-bar configured to enclose coaxially therein a winding roller for the net and to slide in horizontal direction forwards and rearwards to the box; upper and lower closing means of the box and upper and lower closing means of the handle-bar; a screening net interposed between said box and said bar, said net being fastened to an end to the box and to the other one to said winding roller; a couple of guide means (6, 6'), respectively lower and upper, for the net, said guide means (6, 6') being fastened to an end to said closing means of the handle-bar and having the opposite end configured to be able to slide inside the box; said moving means (9, 10) are interposed between said upper and lower closing means of the box; said insect screen being characterized in that - said moving means of the net comprise a couple of gear wheels configured to be coaxially rigidly coupled to an innerly hollow cylindrical element interposed between said couple of gear wheels inside a hollow seat of the box, so that the upper gear wheel can interact with said upper guide means and the lower gear wheel can interact with said lower guide means, - said guide means (6, 6') are configured to interact mutually with said moving means (9, 10) so that upon an outer action on the handle-bar the rotation of at least a gear wheel causes a displacement of said upper guide means with equal pitch as the one of said lower guide means or vice versa. - said moving means of the net comprise a couple of gear wheels configured to be coaxially rigidly coupled to an innerly hollow cylindrical element interposed between said couple of gear wheels inside a hollow seat of the box, so that the upper gear wheel can interact with said upper guide means and the lower gear wheel can interact with said lower guide means, - said guide means (6, 6') are configured to interact mutually with said moving means (9, 10) so that upon an outer action on the handle-bar the rotation of at least a gear wheel causes a displacement of said upper guide means with equal pitch as the one of said lower guide means or vice versa.