A high-speed type burner tile assembly including a cylindrical mixing tile having a central through-hole, and a combustion tile having a tip portion aligned with the mixing tile. The tip portion of the combustion tile is coaxially extended into the central cylindrical through-hole of the mixing tile to provide diffusion air delivery passages extending in parallel with the axis of the mixing tile between the tip portion and the inner surface of the through-hole of the mixing tile, thereby permitting the supply of a large volume of diffusion air at low pressures and increasing linearity of the combustion gas supplied into a furnace.