The invention belongs to the field of cigarette processing and particularly relates to a method for improving cut tobacco bulkiness, and a device for implementing the method. The method includes: analyzing the structure of dry cut tobacco, screening to obtain clustered cut tobacco, and tearing the clustered cut tobacco to improve the bulkiness. The device comprises two rollers, and both surfaces of each roller are provided with needle plates, while the ends of the rollers are coplanar. The method is simple. The device is reasonable in design, simple in structure and low in cost. The method and the device have the advantages that cut tobacco bulkiness is improved while large-scale modification is unavailable for the existing cigarette making equipment, and great contribution is made to improving the quality of finished cigarettes.