An end apparatus for a burner configured to generate a flame, comprising: - a combustion head connectable to supply means for supplying a fuel and having at least one inlet opening, adapted to enable a fuel to enter, and a plurality of outlet openings, adapted to enable an outflow of fuel; - a comburent supply conduit configured to convey a comburent to said combustion head and extending between a comburent introduction opening and an emission opening along a main extension direction; wherein said combustion head is at least partially inserted into said supply conduit, at the emission opening, so as to define a passage gap between said combustion head and said supply conduit for a flow of comburent; wherein said combustion head comprises: - a plurality of outer openings arranged outside said passage gap according to a direction that is radial to said main extension direction and configured to emit a first flow of fuel outside said flow of a comburent; and - a plurality of inner openings arranged at and/or inside said passage gap according to a direction that is radial to said main extension direction, said inner openings being adapted to introduce a second flow of fuel (F2', F2") inside said flow of a comburent; wherein said combustion head comprises a central body at least partially inserted into said supply conduit and extending between a first end, defining said inlet opening, and a second end along an extension direction; said second end defining with said supply conduit at least partially said passage gap; wherein said second end has a convergent portion, preferably truncated conically shaped, along said extension direction and defines with said supply conduit at least partially said passage gap; wherein said second end has at least one divergent portion along said extension direction characterized in that said divergent portion is arranged at least partially inside said convergent portion. - a combustion head connectable to supply means for supplying a fuel and having at least one inlet opening, adapted to enable a fuel to enter, and a plurality of outlet openings, adapted to enable an outflow of fuel; - a comburent supply conduit configured to convey a comburent to said combustion head and extending between a comburent introduction opening and an emission opening along a main extension direction; wherein said combustion head is at least partially inserted into said supply conduit, at the emission opening, so as to define a passage gap between said combustion head and said supply conduit for a flow of comburent; wherein said combustion head comprises: - a plurality of outer openings arranged outside said passage gap according to a direction that is radial to said main extension direction and configured to emit a first flow of fuel outside said flow of a comburent; and - a plurality of inner openings arranged at and/or inside said passage gap according to a direction that is radial to said main extension direction, said inner openings being adapted to introduce a second flow of fuel (F2', F2") inside said flow of a comburent; - a plurality of outer openings arranged outside said passage gap according to a direction that is radial to said main extension direction and configured to emit a first flow of fuel outside said flow of a comburent; and - a plurality of inner openings arranged at and/or inside said passage gap according to a direction that is radial to said main extension direction, said inner openings being adapted to introduce a second flow of fuel (F2', F2") inside said flow of a comburent; wherein said combustion head comprises a central body at least partially inserted into said supply conduit and extending between a first end, defining said inlet opening, and a second end along an extension direction; said second end defining with said supply conduit at least partially said passage gap; wherein said second end has a convergent portion, preferably truncated conically shaped, along said extension direction and defines with said supply conduit at least partially said passage gap; wherein said second end has at least one divergent portion along said extension direction characterized in that said divergent portion is arranged at least partially inside said convergent portion.