The invention relates to a full-sealing device for a cutting component of a roadheader, wherein the full-sealing device is of a non-telescopic structure. The novel full-sealing device comprises a first seal, a second seal and a third seal. The first seal is formed by an outer cylinder, a steel plate, a clamp ring and a carbon fiber packing, wherein the outer cylinder is sleeved with the steel plate, the steel plate is sleeved with the clamp ring, and the carbon fiber packing is arranged between the steel plate and the rear end of a cutting head. The second seal is formed by a floating sealing frame, a floating sealing base, a floating seal and a sealing ring, wherein the floating sealing frame is arranged at the front end of the outer cylinder, the floating sealing base is arranged between the floating sealing frame and the cutting head, the floating seal is arranged between the floating sealing frame and the floating sealing base, and the sealing ring is arranged on the outer side of the floating seal. The third seal is formed by a radial oil seal arranged between the floating sealing frame and the floating sealing base, and the radial oil seal is located at the back of the floating seal. According to the full-sealing device, pollutants are sealed according to different ranks, the sealing effect is good, normal running of bearings in the cutting component is guaranteed and trouble spots of a machine are reduced, and the full-sealing device is simple in structure and convenient to assemble and disassemble.