The invention relates to the technical field of coking equipment, in particular to an automatic sampling device. A material taking rod is rotatably arranged on a door-shaped frame close to a sampling port of equipment to be sampled, the bottom of the material taking rod is connected with a material taking hopper, and an electric push rod connected with a timer is arranged on a support frame connected with the door-shaped frame; the telescopic end of the electric push rod is connected with the material taking rod so as to push the material taking rod to swing, then the material taking hopper is driven to take and place materials, and therefore automatic material taking can be achieved. By adopting the sampling device, manual sampling is cancelled, the safety problem of personnel sampling under the condition of equipment operation is greatly reduced, the safety risk is controlled, standardized sampling operation is realized, the sampling standard and the sampling efficiency are improved, manpower, material resources and related cost are reduced, and mechanical automation of sampling is realized; and the sampling device is suitable for various sampling operations, and is simple, convenient, high in practicability and wide in application.