A processing cell of automatic machining system configured in that it is easy to decide or change the number of steps and to design, and to reduce the installation cost. The control unit of the processing cell comprises an operation data storing means for storing every position necessary data for operation at each position of the processing cell installed in the machining section of the automatic machining system, and a position designating means for designating the after-installation position. The control unit reads necessary data for operation out of the operation data storing means in accordance with the position designated by the position designating means. Thus, the operation of each cell can be switched in accordance with the position, and the processing cells can be easily changed in position and adjusted in quantity.