Abstract: The invention relates to a burner for solid fuel such as biomass or tyres, that comprises a heating body in the shape of a cylinder (1,1?, 1?) with solid fuel supply means and means for the inlet of primary air (13, 13?, 13?) as oxidant, said cylinder being provided with a plate (3,3?,3?) in its lower part. The invention comprises placing the plate above the means for the inlet of primary air (13, 13?, 13?), wherein the plate has through holes and is arranged so as to receive the fuel without the fuel flowing therethrough, and said burner further includes inside said cylinder (1, 1?,1?) means for generating a negative pressure within the burner so as to generate a primary air circulation from the underside of the plate (3, 3?,3?) and through said plate and the fuel resting thereon up to a gas outlet duct (4, 4?, 4?) in the upper portion of said burner. Application in the combustion of biomass, tyres and the like.