An apparatus is situated downstream of a stickpack manufacturing machine with multiple dropping channels for forming a same number of stickpacks, which are distanced from one another by an interaxial measurement which is more than twice the width of the stickpacks. The apparatus comprises a ring-wound conveyor line, in which two batteries of walled compartments are provided, which batteries are driven independently from each other so that each battery is alternately situated either upstream or downstream; the number of compartments of each is a multiple of the number of dropping channels; the compartments are distanced by a step which is equal to half the interaxial measurement. A robotic handler is provided upstream of the conveyor line, which handler collects the stickpacks exiting from the machine and piles the stickpacks in the compartments of the battery waiting there; first the compartments in odd order, i.e. first, third and so on are filled, then the battery is made to advance by a step in order to fill the compartments in even order, i.e. second, fourth and so on, until all the compartments of the battery have been filled. In a phase relation with a return upstream of the remaining battery, the battery with filled compartments is transferred to a downstream cartoning machine, where a pusher acting transversely to the line transfers at least one pile of stickpacks of a compartment to an adjacent carton, which is carried in synchrony of position and advancement by a relative supply line which is partially flanking the conveyor line.