A machine to manufacture cartridges for electronic cigarettes comprising a casing made of plastic material having a microperforated bottom wall and a side wall and containing a quantity of powdered tobacco on top of which a cylindrical portion of filtering material is arranged; the manufacturing machine comprises: a feeding conveyor which feeds a plurality of empty casings in correspondence to a collecting station (PS); a drum rotating at a predetermined pitch around its own vertical rotation axis, which receives an orderly mass of empty casings from the feeding conveyor in correspondence to a collecting station (PS) and feeds them to a first station (FS), in which a quantity of powdered tobacco is inserted into each empty casing , and, subsequently, to a second station (FRS), in which a portion of filtering material is inserted into each casing ; a filling unit arranged in correspondence to the first station (FS) for feeding a quantity of powdered tobacco inside each empty casing from above; and a feeding unit arranged in correspondence to the second station (FRS) to insert a portion of filtering material into each casing from above; the manufacturing machine is characterized in that the feeding unit comprises a bent panel which receives rods of filtering material divided into portions of desired length with a horizontal axis and releases them to a store divided into a number of channels ; wherein each of said channels comprises a stack of portions of filtering material arranged one on top of the other with a vertical axis; and wherein the feeding unit further comprises a lower guide associated with the store which cooperates with a first arm mobile in a horizontal direction to insert a portion of filtering material into each casing from above. a feeding conveyor which feeds a plurality of empty casings in correspondence to a collecting station (PS); a drum rotating at a predetermined pitch around its own vertical rotation axis, which receives an orderly mass of empty casings from the feeding conveyor in correspondence to a collecting station (PS) and feeds them to a first station (FS), in which a quantity of powdered tobacco is inserted into each empty casing , and, subsequently, to a second station (FRS), in which a portion of filtering material is inserted into each casing ; a filling unit arranged in correspondence to the first station (FS) for feeding a quantity of powdered tobacco inside each empty casing from above; and a feeding unit arranged in correspondence to the second station (FRS) to insert a portion of filtering material into each casing from above; the manufacturing machine is characterized in that the feeding unit comprises a bent panel which receives rods of filtering material divided into portions of desired length with a horizontal axis and releases them to a store divided into a number of channels ; wherein each of said channels comprises a stack of portions of filtering material arranged one on top of the other with a vertical axis; and wherein the feeding unit further comprises a lower guide associated with the store which cooperates with a first arm mobile in a horizontal direction to insert a portion of filtering material into each casing from above. <EOS>