A separation device for a spacecraft or launcher comprising a nut divided into at least two nut portions locked to each other by a locking device in a locking position. A releasing device is arranged to switch the locking device from the locking position to a releasing position. The separation device comprises at least two bearing elements arranged between the locking device and the nut. The nut comprises an outer envelope surface which comprises as many indentations as the number of bearing elements and locking surfaces between the indentations. In the locked state each bearing element is jammed between the locking surface and an inner envelope surface of the locking device and in the released state each bearing element is positioned facing the indentations.