The invention relates to a module for extending a retractable insert of a key, in particular for a motor vehicle, which is intended to be mounted in a casing for said key and which comprises an insert (5, 7), intended to be pivotably mounted relative to said casing (3) between an inoperative and an operative position, and comprising a bit (7) and a bit holder (5), which is pivotably mounted relative to said casing (3), and a mechanism for extending the insert (5, 7), which includes a push-button (19), and an elastic return element (23) for the insert (5, 7) consisting of a helical torsion spring, one end (23a) of which is connected to the insert (5, 7), in order to urge the insert (5, 7) by pivoting towards said operative position, when the push-button (19) is actuated. According to the invention, the push-button (19) comprises a projection (49) for holding the insert (5, 7) in the inoperative position and in the operative position, the mounting position of said projection being different from said inoperative and operative positions.