A device for finely adjusting the length of a bracelet inserted between two elements of the bracelet and includes an outer part attached to one, an inner part attached to the other and to slide in the outer part parallel to the longitudinal direction of the bracelet, causing the length of the bracelet to be varied, and a stop arranged to limit the travel of the inner part relative to the outer part so the bracelet cannot be extended beyond a maximum length. The outer part includes a wall having an immobilization hole on its inner side. The inner part includes a pivoting lever with a first end biased by a spring toward the outer part wall, permitting the first end to engage the immobilization hole, immobilizing the inner part relative to the outer part. The inner part has a control member permitting manual control of the lever.