Abstract: The present invention relates to a transparent security shutter, of the type that can be wound about a drum arranged at the top thereof, said shutter being made up of a plurality of transparent slats (3), arranged horizontally on top of one another, and each connected to the immediately higher slat by means of two profiles (4, 5) with engaged matching sections, the shutter furthermore being of the type in which the slats are inserted between the profiles (4, 5) and in which the profiles and/or the slats slide, at either end thereof, in a vertical lateral slide (6) attached to the opening (??) which delimits the window to be protected, characterized in that each one of the slats thereof is made up of a plurality of I-section modules (7, 12) assembled two-by-two in a laterally overlapping fashion, the top (20) and bottom (21) flanges of said modules being inserted by sliding between two opposing rails (22, 23), provided on the surfaces of the profiles opposite the locking surfaces thereof, respectively the top