A regulation and/or locking device (1) of a plate (100) is suitable for cooperating with one of its sides (101, 102) so as to lock it in a predefined position. The device (1) has two gibs (10) facing one another, where each gib (10) has a support surface (11), positioned towards the outside and suitable for resting on the respective face (101, 102) of the plate or on a fixed element, and positioning surfaces (12), inclined with respect to the support surfaces (11). The device also includes positioners (50) interacting with the positioning surfaces (12) in such a way as to move the position of the gibs (10) locking the plate (100) and controllers (60) maneuverable to activate the positioners (50).