The invention relates to a bearing restraining device outside a tube shell of a spiral conveyer. The gearing restraining device comprises a shell, a spiral shaft is arranged inside the shell and provided with a spiral blade, the shell is fractured, a bearing is arranged at the fractured position of the shell, an inner ring of the bearing is connected with the spiral blade, and an idler wheel arranged outside the inner ring of the bearing is arranged inside an idler wheel holder which is connected with a flange. By the adoption of the structure, compared with a bearing support arranged in a tube, the bearing restraining device has the advantages that no bearing or support is arranged inside the tube, the spiral blade is not fractured and has no notch, and impact, damage and vibration caused to the notch and the support by hard lumps of materials are avoided; the materials are conveyed smoothly, efficiency is improved, and energy consumption and maintenance cost are lowered; noise is reduced, and the working environment is improved; no lubricating oil leaks in the tube, and the materials cannot be polluted.