Welding unit for an automatic flexible pouch forming machine comprising: - first and second pressure applicators facing one another, thereby forming a first path for a first pouch precursor made of a folded band of flexible heat-sealable film, - heating means heating at least one of said first and second pressure applicators , and - driving means for moving at least one of said first and second pressure applicators between a release position, in which the first and second pressure applicators are separated from the first path, and a welding position, in which the first and second pressure applicators press and apply heat on the first pouch precursor to form a weld, characterized in that it comprises: a first lateral element comprising the first pressure applicator ; a central element comprising the second pressure applicator and a third pressure applicator on opposite sides thereof; a second lateral element comprising a fourth pressure applicator facing the third pressure applicator , thereby forming a second path for a second pouch precursor made of a folded band of flexible heat-sealable film; wherein the heating means also heat at least one of said third and fourth pressure applicators ; and wherein at least one of said third and fourth pressure applicators are movable between a release position, in which the third and fourth pressure applicators are separated from the second path, and a welding position, in which the third and fourth pressure applicators press and apply heat on the second pouch precursor to form a weld; and wherein at least one of the third and fourth pressure applicators is operatively connected to said driving means , so that at least one of said first and second pressure applicators and at least one of said third and fourth pressure applicators , simultaneously move from the release position to the welding position, and vice versa. - first and second pressure applicators facing one another, thereby forming a first path for a first pouch precursor made of a folded band of flexible heat-sealable film, - heating means heating at least one of said first and second pressure applicators , and - driving means for moving at least one of said first and second pressure applicators between a release position, in which the first and second pressure applicators are separated from the first path, and a welding position, in which the first and second pressure applicators press and apply heat on the first pouch precursor to form a weld, a first lateral element comprising the first pressure applicator ; a central element comprising the second pressure applicator and a third pressure applicator on opposite sides thereof; a second lateral element comprising a fourth pressure applicator facing the third pressure applicator , thereby forming a second path for a second pouch precursor made of a folded band of flexible heat-sealable film; wherein the heating means also heat at least one of said third and fourth pressure applicators ; and wherein at least one of said third and fourth pressure applicators are movable between a release position, in which the third and fourth pressure applicators are separated from the second path, and a welding position, in which the third and fourth pressure applicators press and apply heat on the second pouch precursor to form a weld; and wherein at least one of the third and fourth pressure applicators is operatively connected to said driving means , so that at least one of said first and second pressure applicators and at least one of said third and fourth pressure applicators , simultaneously move from the release position to the welding position, and vice versa. <EOS>