Device for rapid engagement/release of units (1) for fitting lids to containers, comprising a fixed part (100) and a movable part (200) which can be reversibly coupled to the fixed part (100), said fixed part comprising means (112) for housing corresponding first radial elements (213a) integral with the movable part (200) and such as to allow the movement in an axial and/or radial direction of the said movable part (200), there being provided first locking means (111) associated with the fixed part (100) and able to co-operate with corresponding second radial elements (213) of the movable part (200) so as to prevent displacement in an axial direction thereof, and second locking means (130,132) coaxially movable on the fixed part (100) and able to co-operate with said first radial elements (213a) so as to prevent the rotation of the movable part (200).