To provide a plastic working apparatus capable of reducing variations in the thickness of a formed product at a low cost even when plastically working a cylindrical stock into a thin-walled shape of 0.1 mm in thickness.

The plastic working apparatus comprises a die 3, which is arranged at the front end of a main shaft 2, and a drawing roller R for plastically working the circumferential surface of a cylindrical stock W, which is attached to the die 3. Further, the plastic working apparatus is provided with a measuring instrument 6 for measuring the length of the cylindrical stock W under working and a control mechanism 7 for changing working conditions according to the measured value by the measuring instrument 6.