Abstract: A sintering furnace for sintering an object to be sintered formed of ceramics, fine ceramic materials, etc. to produce a sintered object and a method therefor. An insulating wall (28) and an inner shell (25) define a sintering chamber (16) for sintering an object to be sintered (10). Thermal equilibrium is maintained between the inner shell (25) and the object to be sintered (10), and the object to be sintered (10) is completely pseudo-adiabatically isolated to achieve more uniform and small energy consuming sintering. The thickness of the insulating wall (28) increases gradually from an inlet (20) toward an outlet (21). The object to be sintered (10) is fed by a carriage provided in a sintering furnace from the inlet (20) to the outlet (21) in the sintering chamber (16). Thereby, a temperature distribution corresponding to a plurality of processes can be easily formed in one furnace to sinter continuously the object to be sintered (10) in the furnace.