Sealed connection device between a first and a second closed space, closed off by doors, first part (A) for securing the first and second flanges to one another, second part for securing the second door and the first door in a sealed manner, part for detaching the second door from the second flange, third part for releasing the first door in relation to the first flange (18), fourth part for opening a passage between the first and the second closed space, and part for controlling the first, second, third and fourth parts allowing for the sealed connection without rotation of one of the closed spaces, the device also comprising a device for maintaining by snap fitting (34) for the second closed space in relation to the first closed space prior to the securing by the first part for securing.