A gaseous fuel burner for low pollutant emissions and greater heat transfer, said burner consists of an outer housing which defines a distal end for the outlet of the flame and a proximal end for the supply of the gaseous fuel and air; both having covers (4,5); a pressurized air inlet is placed on the outer housing wall near the proximal end defining an inner pressurized air supply perimeter chamber; the cover of the proximal end receives affixed on the center a pressurized gaseous fuel supply duct, whose end portion is housed in the interior of a first mixing chamber placed in the interior of said housing, which includes a cover on its proximal end through which said pressurized gaseous fuel supply duct is connected and is open in its distal end; said end portion of said pressurized gaseous fuel supply duct includes a variety of orifices in its wall for the outlet of the gaseous fuel towards said first mixing chamber; said cover of the proximal end of said first mixing chamber, as well as its wall include a variety of orifices to supply pressurized air axially and radially from said inner pressurized air supply perimeter chamber, to generate a first turbulent mixture of gaseous fuel - air to the interior of said first mixing chamber; an igniter element is placed in the interior of said first mixing chamber to generate a first stage of the combustion process; a second over-mixing open chamber open in both ends, coupled collinearly with said first mixing chamber housed within said outer housing, where the distal end of said pressurized gaseous fuel supply duct comprises a cone that ends at an obstruction cover that is placed centrally to the limit of the border between said first mixing chamber and said second over-mixing chamber; where said obstruction cover of the pressurized gaseous fuel supply duct comprises a variety of orifices through which a turbulent flow of gaseous fuel is supplied axially towards said second over-mixing chamber and the wall of said second over-mixing chamber consists of a variety of orifices through which pressurized air is supplied radially from said inner pressurized air supply perimeter chamber to generate a second enriched, turbulent gaseous fuel - air mixture and where a second stage of the combustion process takes place; said cover of the distal end of said outer housing consists of a central opening in which said second chamber of over-mixing leads into and where: towards the interior of the outer housing in the inlet of pressurized air, a concave deflector which allow the uniform distribution of the air in the interior of the inner pressurized air supply chamber is placed, said concave deflector is affixed to the interior of said cover of the proximal end of the outer housing, and at least two deflector plates, separated between each other and affixed radially in the inner wall of said outer housing and in said concave deflector; the distribution and arrangement of the deflectors allow an homogeneous flow of air in all the interior of said inner pressurized air supply perimeter chamber. towards the interior of the outer housing in the inlet of pressurized air, a concave deflector which allow the uniform distribution of the air in the interior of the inner pressurized air supply chamber is placed, said concave deflector is affixed to the interior of said cover of the proximal end of the outer housing, and at least two deflector plates, separated between each other and affixed radially in the inner wall of said outer housing and in said concave deflector; the distribution and arrangement of the deflectors allow an homogeneous flow of air in all the interior of said inner pressurized air supply perimeter chamber.