The invention provides a dagger drill on one hand. The dagger drill comprises a head segment (1), a tail segment (3), and a middle segment (2) for connecting the head segment (1) and the tail segment (3). A continuous blade (4) is arranged around an axis direction (L) of the dagger drill from the head segment (1), the middle segment (2) to the tail segment (3); the end head of the head segment (1) forms a tip (11); and the diameter of the blade (4) is gradually increased from the first segment (1) to the middle segment (2). The invention also provides a method for hole processing on the other hand. According to the dagger drill and the method for hole processing provided by the invention, the improvement of the processing efficiency, the reduction of the layering risk of hole processing, and the improvement of the quality of a hole can be realized at least.