An apparatus (10) for laying wire ties, which comprises, on a supporting body (12): - a front portion (13), which in turn comprises a hook-shaped guide (16) that is open inwardly, with a movable end portion (17) to be closed on an abutment element (19) so as to surround the items to be tied, - a first motor (20), for moving the movable portion (17) of the hook-shaped guide (16), - a second motor (21), for the continuous feeding of a flexible wire (22) in succession along a rear portion (15) of the apparatus (10), along the hook-shaped guide (16) and along the abutment element (19), when the movable portion (17) is closed on the latter, - means (23) for cutting the flexible wire (22), so as to separate a tie (14) thereof that substantially occupies the front portion (13), - a third motor (24) for the rotation of a twister (25) adapted to twist a first portion (27) of the tie (14) with a last portion (28).