Abstract: The purpose of the invention is a railway track (3) sleeper (2) squaring device and the machine which carries this device. The device comprises a first and a second positioning element (1) adapted to be located between pairs of sleepers (2) and for locating at opposite ends of the sleepers (2) and parallel to the direction of the railway track (3) where these positioning elements (1) can be extended in that direction with the first and second positioning element (1) being configured such that on extending them simultaneously to a pre-set value they push the sleepers (2) so as to produce squaring of these sleepers (2).