To form a part or a whole circumference of a material to be worked having a cylindrical shape into a deflected or an inclined shape with a stable molding accuracy.

In a method for forming the material, a forming work against the material to be worked W having the cylindrical shape is performed by a forming device 1 provided with a tool fixing mechanism 3 having a working tool 4 and a holding mechanism 2 for holding the material to be worked W having the cylindrical shape provided and opposed to the working tool 4. A core bar 5 is inserted into the material to be worked W through the deflection or the inclination and the working tool 4 provided with a buffer mechanism 40 is rotated relatively with the material to be worked W and the core bar 5, while pressing the working tool 4 against the material to be worked W and by relatively displacing the working tool 4 in the axial direction of the material to be worked W, the material to be worked W can be formed into a shape corresponding to the core bar 5.

COPYRIGHT: (C)2005,JPO&NCIPI