The invention relates to a rotary hearth furnace. The rotary hearth furnace comprises a furnace body, a furnace bottom, a temperature measuring device and a combustor, wherein the furnace body is provided with a feeding hole and a discharging hole; the cross section of the furnace body is in a circular ring shape; the furnace bottom is circular-ring-shaped in appearance; an annular reaction space is defined by the inner ring sidewall and the outer ring sidewall of the furnace body and the upper surface of the furnace bottom; the temperature measuring device is mounted at the furnace bottom; a temperature measuring end of the temperature measuring device is placed in the reaction space; the combustor is mounted on the sidewall of the furnace body. By arranging the temperature measuring device in the reaction space of the rotary hearth furnace, the rotary hearth furnace provided by the invention is capable of accurately measuring the actual temperature of a material so as to control the actual temperature of the material to be optimal, so a good reaction effect can be achieved.