The invention relates to the field of mobile gas supply, and discloses a follow-up gas supply device. The follow-up gas supply device comprises a gas cylinder and an electric control box, and the gas supply end of the gas cylinder is connected with a pipeline with an inlet power gas source valve, a pipeline with a protective gas source valve and a pipeline with an outlet power gas source valve; and the electric control box is used for receiving and analyzing external signals and controlling the opening degrees of the inlet power gas source valve, the protective gas source valve and the outlet power gas source valve. The invention further provides a tank car comprising the follow-up gas supply device. According to the follow-up gas supply device and the tank car, under the condition that near distance operation is not needed, protective gas, valve power gas and the like are provided for material tanks for storing and conveying materials such as hot semi-coke with requirement for isolation from external air.