Abstract: An improvement in an apparatus for setting up and closing the bottom of cartons or so called slit-boxes which are supplied as plainly collapsed carton tubes having sides and bottom and top flaps which are integral with the sides. The apparatus comprises a support (1) which carries a magazine (2) for carton blanks, a feeder unit (3) and a bottom flap closing means (4). The feeding unit (3) includes a suction catcher (11) adapted to catch and open a container blank and to move the said blank along a handling path while closing at least bottom thereof. The feeding unit carries an expelling means (27) having an expellor arm (28) which is moveable between a position inside the handling path and a position outside the handling path and which is mounted at a predetermined distance in front of the feeder unit (3) as considered in the feeding direction.