Novel expansion drill bit

The utility model discloses a novel expansion drill bit comprising drill bit bodies, movable holes, an outer clamp plate, a clamp plate, a drill rod and fixing holes. The inner ends of the drill bit bodies are arranged inside the clamp plate symmetrically through the fixing holes, and the other ends are connected with the outer clamp plate when the drill bit bodies are expanded. The movable holes are formed inside the drill bit bodies. The bottom end of the clamp plate is connected with the drill bit bodies while the top end of the same is connected with the drill rod. The fixing holes are formed in the joints of the clamp plate and the drill bit bodies symmetrically. The novel expansion drill bit has the advantages that the condition that a conventional drill bit is just limited to a certain area to apply pressure is changed; due to the expansion effect, area of pressure application is enlarged, further operating time is saved, the technical problem that an extraction resistant anchor eye is small in upper c