The present invention provides a combustion method and apparatus for melting a combustible material, such as waste materials, coal, etc. are vaporized sufficiently large amount of self-heat material generates a combustion gas containing a component of the combustion. Fluidized-bed furnace (2) it has a substantially circular cross-sectional profile of. A moving bed (9) for the flow medium staying diffusion is formed in the central portion of the furnace, the fluidized bed 10, the fluidizing medium is actively flow is formed in the peripheral portion of the furnace. The fluid medium is directed to the top of the moving bed (9) from the top of the fluidized bed 10 and circulating the two layers. Combustion material 11 is gasified is introduced to the top of the moving bed 9, to form a combustible gas while circulating together with the fluid medium. The amount of oxygen supplied to the fluidized-bed furnace 2 is set equal to that contained in air of less than 30% of the theoretical combustion air amount. Temperature of the fluidized bed 10 is maintained at 450 ℃ to 650 ℃, and the generated combustion gas contains a large amount of combustion components. Fluidized-bed furnace 2, the combustion gas and fine particles produced in the melt is supplied to the furnace is combusted at a high temperature as a result material is produced it is melted.