The invention relates to the technical field of atmosphere mobile detection, in particular to a carrying device used for an atmosphere detection vehicle. The carrying device comprises a trolley arranged on the rear portion of a bottom plate of a vehicle body. The trolley is arranged in the front-back direction of the vehicle body in a sliding manner. First rolling wheels are arranged at the frontend of the trolley. Second rolling wheels are arranged at the rear end of the trolley. Third rolling wheels are arranged on the middle portion of the trolley. The first rolling wheels, the second rolling wheels and the third rolling wheels are all matched with the bottom plate of the vehicle body in a rolling manner. A self-rebounding joint is arranged on an axle of each second rolling wheel. A reflection unit of an atmosphere infrared spectrum detection system is installed on a lifting cart. A cart releasing mechanism and a cart recycling mechanism are arranged on the trolley. The release scheme of horizontally moving the whole reflection unit to the outer portion of the vehicle body firstly and then horizontally moving the whole reflection unit to the ground in the vertical direction isadopted, and by means of the scheme, it can be ensured that the reflection unit is kept in the upright posture all the time in the unloading process and impact on optical elements in the reflection unit is reduced.