To make it possible to suppress the damage minimum in case laundries are ignited by improving a laundry drier.

An inlet temperature sensor 9 is arranged in the hot-air flow inlet of an inner cylinder 1a (near the hot-air blow out port of a heater 2) and an outlet temperature sensor 10 is arranged in the hot-air flow outlet of the inner cylinder 1a (near the hot air suction port of a blower 3). Detected signals by the above sensors are input into an automatic control unit 11 and compared and calculated, and the temperature difference between both the temperatures reaches a predetermined value, then it is estimated that the laundries are ignited, thereby an inlet door 4, an outlet door 5, a hatch, and a damper 3b are completely closed, and the laundry drier is urgently stopped.