The utility model relates to a moisture removing device, particularly to a moisture removing device of a terminal box. With the moisture removing device, a problem that the element in the existing terminal box rusts because element ventilation is not carried out timely can be solved. One terminal of a starting switch of a hygrometer, one terminal of a stopping switch of the hygrometer, and one terminal of a second contact normally-open switch of an alternating-current contactor, and one terminal of a third contact normally-open switch are connected; the other terminal of the stopping switch is connected with one terminal of a first contact normally-open switch of the alternating-current contactor; the other terminal of the first contact normally-open switch is simultaneously connected with the other terminal of the starting switch and one terminal of a control coil of the alternating-current contactor; the other terminal of the second contact normally-open switch is connected with one terminal of a power supply of an exhaust fan; the other terminal of the third contact normally-open switch is connected with one terminal of a power supply of a heater; and the other terminal of the control coil and the other terminal of the power supply of the exhaust fan are simultaneously connected with the other terminal of the power supply of the heater. Besides, a 220-V power supply provides power for the circuit by two air switches. The provided moisture removing device is used for carrying out moisture removing on the terminal box.