Diamond bit

The utility model provides a diamond bit, which belongs to the technical field of machinery, which solves the technical problems of poor cooling effect, easiness in being burst of bit edges. The diamond bit comprises bit edges, a drill rod and a connecting rod. One end of the tubular drill rod is open, the bit edges are distributed on the outer edge of the open end of the drill rod, the connecting rod is axially and fixedly connected with the other end of the drill rod, a water inlet communicated with an inner cavity of the drill rod is arranged on the side wall of the drill rod, the length direction of the elongated water inlet is parallel to the axial direction of the drill rod, and the area of the water inlet is half to one eighth of that of the drill rod. The diamond bit allows passage of a great deal of cooling liquid, accordingly cooling effect of the bit edges is improved, and wear resistance of the bit edges is enhanced greatly.