The invention relates to an asynchronous device of a transmission. The asynchronous device comprises a plurality of asynchronous cones, asynchronous rings and tooth sleeves, wherein cone angles are separately arranged on one side of every asynchronous cone, asynchronous ring and tooth sleeve, the generatrixes of the cone angles of the asynchronous cones-the connecting lines from the peak of each asynchronous cone to any point on circumference--are not in equal length, the generatrixes of cone angles of the tooth sleeves are not in equal length, and the generatrixes of cone angles of the asynchronous rings are not in equal length, thus the smoothness, comfort and reliability of gear-switching are increased.