The invention relates to displacement encoder for a movable shaft, comprising a sleeve (2) which is intended to be fixed in rotation to the shaft (3) and an encoding element (4) which is made from magnetizable polymer and which is solidly connected to the sleeve, said encoding element being equipped with an encoding zone (6) having at least one polarized mark. The aforementioned encoding zone of the encoding element is covered with a protective layer (10) which is made from a polymer having a surface abrasion resistance greater than that of the magnetizable polymer. The invention also relates to a device comprising one such encoder and to a production method thereof.