A feeding unit for feeding tobacco to a manufacturing machine for the production of disposable cartridges for electronic cigarettes; the feeding unit comprising: a tank, which is designed to contain a tobacco mass and has a first bottom wall provided with at least a first output through opening; and at least one conveyor, which is arranged under the tank in alignment with the first output opening, is designed to receive the tobacco falling, due to gravity, through the first output opening, and is designed to move the tobacco along a moving path; wherein the conveyor is a vibrating conveyor and comprises: a second bottom wall mounted so as to vibrate along a vibration direction, side walls arranged vertically and extending from the second bottom wall, and at least one actuator, which is coupled to the second bottom wall and is designed to cause a vibration of the second bottom wall along the vibration direction; the feeding unit being characterized in that: the conveyor comprises a second upper wall, which has a second input through opening, which is aligned with the first output opening; the side walls extend from the second bottom wall to the second upper wall so as to give the conveyor a closed shape; the feeding path extends from the second input opening to a second output opening made through the second bottom wall at the end of the moving path; the feeding unit comprises a servo-controlled valve, which is arranged between the first output opening of the first bottom wall of the tank and the conveyor and can be activated to transfer the tobacco towards the conveyor or, alternatively, can be deactivated to prevent the tobacco from falling, due to gravity, towards the conveyor; whereby the servo-controlled valve is automatically deactivated when the conveyor is standing still and is automatically activated when the conveyor is active. a tank, which is designed to contain a tobacco mass and has a first bottom wall provided with at least a first output through opening; and at least one conveyor, which is arranged under the tank in alignment with the first output opening, is designed to receive the tobacco falling, due to gravity, through the first output opening, and is designed to move the tobacco along a moving path; wherein the conveyor is a vibrating conveyor and comprises: a second bottom wall mounted so as to vibrate along a vibration direction, side walls arranged vertically and extending from the second bottom wall, and at least one actuator, which is coupled to the second bottom wall and is designed to cause a vibration of the second bottom wall along the vibration direction; the feeding unit being characterized in that: the conveyor comprises a second upper wall, which has a second input through opening, which is aligned with the first output opening; the side walls extend from the second bottom wall to the second upper wall so as to give the conveyor a closed shape; the feeding path extends from the second input opening to a second output opening made through the second bottom wall at the end of the moving path; the feeding unit comprises a servo-controlled valve, which is arranged between the first output opening of the first bottom wall of the tank and the conveyor and can be activated to transfer the tobacco towards the conveyor or, alternatively, can be deactivated to prevent the tobacco from falling, due to gravity, towards the conveyor; whereby the servo-controlled valve is automatically deactivated when the conveyor is standing still and is automatically activated when the conveyor is active. the conveyor comprises a second upper wall, which has a second input through opening, which is aligned with the first output opening; the side walls extend from the second bottom wall to the second upper wall so as to give the conveyor a closed shape; the feeding path extends from the second input opening to a second output opening made through the second bottom wall at the end of the moving path; the feeding unit comprises a servo-controlled valve, which is arranged between the first output opening of the first bottom wall of the tank and the conveyor and can be activated to transfer the tobacco towards the conveyor or, alternatively, can be deactivated to prevent the tobacco from falling, due to gravity, towards the conveyor; whereby the servo-controlled valve is automatically deactivated when the conveyor is standing still and is automatically activated when the conveyor is active.