<p>[PROBLEMS] To provide a rotary hearth furnace which is of a general-purpose type, which can properly determine a thermal expansion tolerance in the rotary hearth furnace, and has a simple hearth structure which does not cause any damage to the hearth even after long-term operation. [MEANS FOR SOLVING PROBLEMS] A radial thermal expansion tolerance X defined by formula (2) is set between an outer peripheral or inner peripheral corner refractory material and the refractory material or between the refractory materials, and the requirement represented by formula (1) is satisfied. X + A < V(A<SUP>2</SUP> + B<SUP>2</SUP>) ··(1) wherein A represents the width of an outer peripheral corner refractory material (7); and B represents the height of a support metal material (11) of the corner refractory material (7). X = ([X0=] distance between the outer end part of the outer peripheral support metal material (11) and the inner end part of the inner peripheral support metal material (12) at the operation temperature) - ([X1=] sum of the length at room temperature in a radial direction of a plurality of refractory materials (6) and corner refractory materials (7,8)) ··(2)</p>
