An injured finger fixing device is composed of a hand fixing plate and tying belts. An adjustable finger fixing hole is formed in the middle of the hand fixing plate. An arm placement groove is formedin the left end of the hand fixing plate. A tool plate is arranged at the right end of the hand fixing plate. A tying belt roller is arranged at the front portion of the hand fixing plate. The tyingbelts are tied on the tying belt roller at the same time. The outer ends of the tying belt are provided with nylon hook-and-loop fasteners A. The rear side of the hand fixing plate is provided with anylon hook-and-loop fastener B which can be fastened with the nylon hook-and-loop fasteners A. The adjustable finger fixing hole is composed of a fixing elliptic hole arc, a movable semi-arc jaw, a rotating shaft and an adjusting cam. The fixing elliptic hole arc is directly arranged in the middle of the hand fixing plate. The movable semi-arc jaw and the rotating shaft are fixed to the bottom face of the hand fixing plate. The adjusting cam is fixed to the hand fixing plate. A protruding tip portion of the adjusting cam is arranged on a thumbing handle of the movable semi-arc jaw. The thumbing handle is provided with a shallow rack. Through the rotating adjustment of the adjusting cam, the movable semi-arc jaw is opened and closed relative to the fixing elliptic hole arc, soft cushion layers are arranged on the inner sides of the fixing elliptic hole arc and the movable semi-arc jaw, the structure is simple, and operation is convenient.