A lathe capable of shortening a cycle time of workpiece machining. A lathe includes a first spindle, a second spindle opposite the first spindle, a tool post on which a cut-off tool is provided, and a control unit which controls rotation of the first and the second spindles and further controls relative movement of the first and the second spindles and the tool post to cut-off the workpiece. The control unit adds a rotation speed fluctuation to a rotation speed of the first spindle after rotating the first spindle and the second spindle synchronously and detects a rotation speed of the second spindle. The control unit determines that the workpiece is normally cut-off upon determining that a detected fluctuation in the rotation speed of the second spindle is within a predetermined range.