A unit for over-wrapping filter bags for infusion products obtained from a machine for forming filter bags for infusion products starting from pieces of filter material each containing at least one dose of infusion product and equipped, with the formed filter bag, with a thread and a tag; the unit for over-wrapping comprising at least: - one carousel rotating about a first axis of rotation and equipped with at least one first and one second gripping means movable in rotation about the first axis of rotation along a closed circular trajectory; - a forming station for forming single sheets of over-wrapping material arranged close to the closed circular trajectory of the first and second gripping means; characterised in that it also comprises: - a feeding device, positioned in the forming station, for feeding the single sheets of over-wrapping material prepared in a U-shape, in phase synchronization with the rotation of the carousel, only on the first gripping means; - a first drum for transport of the formed filter bag, rotating about a second axis of rotation parallel to the first axis of rotation, and having gripping means configured to receive the formed filter bags from a preceding station or carousel and to release, in phase synchronization with the corresponding rotations, the filter bags only on the first gripping means equipped with the U-shaped sheet of over-wrapping material; the first gripping means being configured to enable positioning and retaining of the formed filter bag inside the same U-shaped sheet of over-wrapping material; - a closing station of the sheet of over-wrapping material on the formed filter bag arranged close to the closed circular trajectory of the first and second gripping means; the closing station being equipped with at least one sealing gripper connected to movement elements able to move the sealing gripper, in phase synchronization with the rotation of the carousel, from a first position close to the carousel, for collecting the formed filter bag with the sheet of over-wrapping material from the first gripping means, to a second position away from the carousel, for closing the sheet of over-wrapping material and, lastly, to a third position newly close to the carousel, for release of the formed filter bag closed by the sheet of over-wrapping material only to the second gripping means. - one carousel rotating about a first axis of rotation and equipped with at least one first and one second gripping means movable in rotation about the first axis of rotation along a closed circular trajectory; - a forming station for forming single sheets of over-wrapping material arranged close to the closed circular trajectory of the first and second gripping means; - a feeding device, positioned in the forming station, for feeding the single sheets of over-wrapping material prepared in a U-shape, in phase synchronization with the rotation of the carousel, only on the first gripping means; - a first drum for transport of the formed filter bag, rotating about a second axis of rotation parallel to the first axis of rotation, and having gripping means configured to receive the formed filter bags from a preceding station or carousel and to release, in phase synchronization with the corresponding rotations, the filter bags only on the first gripping means equipped with the U-shaped sheet of over-wrapping material; the first gripping means being configured to enable positioning and retaining of the formed filter bag inside the same U-shaped sheet of over-wrapping material; - a closing station of the sheet of over-wrapping material on the formed filter bag arranged close to the closed circular trajectory of the first and second gripping means; the closing station being equipped with at least one sealing gripper connected to movement elements able to move the sealing gripper, in phase synchronization with the rotation of the carousel, from a first position close to the carousel, for collecting the formed filter bag with the sheet of over-wrapping material from the first gripping means, to a second position away from the carousel, for closing the sheet of over-wrapping material and, lastly, to a third position newly close to the carousel, for release of the formed filter bag closed by the sheet of over-wrapping material only to the second gripping means.