The present invention is relative to a scanning device (100) of a laser light beam (7,8) for reading coded information, comprising: an emission source of a laser light beam (7,8), the laser light beam defining an optical path (10a,10b); an optical element (17) for scanning the laser light beam on a support containing coded information; characterized in that it further comprises a linear polarizer (16) located along the optical path (10a,10b) of said laser light beam (7,8), upstream the optical element for scanning (17), said polarizer being apt to linearly polarize a first portion of said laser light beam in substantially one first plane (s) and direct said polarized portion only towards said optical element for scanning.