PURPOSE: To obtain sintered ore having excellent quality regardless of the fluctuation in the moving speed of a pallet by specifically providing the burners in an ignition furnace and controlling the firing area with respect to raw materials at the time of calcining the raw materials in an endless moving grate type sintering machine.

CONSTITUTION: At least two rows of the burners 8, 8' are provided in a transverse direction apart a prescribed spacing with respect to the progressing direction of the pallet 1 in the ignition furnace 6 and ≥1 rows thereof are formed movable in the progressing direction of the pallet 1. As a result, the firing area of the raw material 9 in the pallet 1 is widened from A to A' if the spacing l between, for example, the burners 8 and 8' is increased up to l' by the movement of the burner 8'. The spacing l is, therefore, adjusted according to the moving speed of the pallet 1 and, if, for example, the moving speed of the pallet 1 is higher, the spacing l is increased to widen the firing area A of the raw materials 9. The firing to the raw materials 9 is sufficiently executed by this method and the red hot layer of a good heat pattern is obtd. The sintered ore having the excellent quality is thus produced.