An object is to provide a drying device of a printing press that is capable of securely storing the integrated values of the irradiation times of LEDs and notifying the operator of the replacement timing of the LEDs. Two control parts are provided to control operation of the printing press. The two control parts each store and update integrated values of the irradiation times of the LEDs on one-by-one basis or on a group-by-group basis automatically or arbitrarily, and compare and update the integrated values of one of the two control parts with the integrated values of the remaining control part to keep each of the integrated values of both the control parts update with the latest integrated value.