A gluing unit for one terminal edge of a log and a method applicable inside a machine for the realisation of a log, in which the logs (14) coming from a rewinding machine are fed towards a gluing unit (11) comprising in sequence a lower unwinding roller (16), and a upper feeder belt (17, 26), and immediately downstream of the unwinding roller (16) at least one section of a sloping plane surface (21, 23) of a pre-established length, followed by a vacuum suction roller (24) above which is positioned an upper roller (25), and then a glue distributor (27), an element (19) being envisaged above the unwinding roller (16) which blows on a terminal edge (29) of the log (14) and underneath a photocell (20) to detect the final edge (21), an evacuation surface (34) for the glued log being envisaged, wherein the log fed by the unwinding roller (16) is placed with the position of the free end out of alignment by an angle (.alpha.) according to the log diameter and the pre-established length of the sloped surface section (21, 23) so that the log in this position, rolls down the sloped surface (21, 23) to position itself on the suction roller (24) with its free end of the final edge (29) placed exactly in correspondence with the contact zone with the suction roller (24).
