Abstract: The control device is of the type in which the movable elements for engaging the gear ratios are shifted by means of parallel slidable yokes (40, 42, 46, 48) on which acts a main control finger member (20) which pivots for alternately sliding each of the yokes in at least one direction and causing the engagement of a gear ratio. According to the invention, the device further comprises an auxiliary control finger member (54) which is capable of pivoting about the axis of the control shaft (12) for sliding a yoke (46) of the two lateral end yokes in a first direction and causing the engagement of the reverse gear ratio, it only being possible to shift the other lateral end yoke (48) by means of the main control finger member (20) in the opposite direction for selecting the forward gear ratio of the highest rank.