A packaging unit for producing sealed packages from a tube of packaging material advanced along a first axis includes: at least two jaws arranged on opposite sides of the first axis and movable between a closed position, in which they grip and seal the tube and an open position, in which they are detached from the tube; at least two forming members supported by the respective jaws in a movable manner between a first operating position, in which, in relation to the position of the jaws, they have the maximum distance from one another, and a second operating position, in which they mate with one another and an actuator to produce movement of the forming members; the actuator includes at least one mover connected to both forming members and selectively activated to perform opposite strokes, along which the mover itself produces the movement of each forming members.