Abstract: A method of machining cylindrical workpieces, mainly cylindrical metallic workpieces such as cylindrical separate metallic workpieces and sequentially fed bar-like workpieces, into cylindrical products such as bearing outer and inner races and valve spools, by employing a bi-spindle numerically controlled machine tool provided with two parallel spindles capable of holding and rotating workpieces, respectively, and a single tool block unit capable of moving in two mutually orthogonal directions under the control of a numerical controller in accordance with a numerical control program, to precisely feed two separate groups of cutting tools mounted thereon and thereby accurately cut the rotating workpieces on the two parallel spindles alternately or simultaneously at a high production rate.