To keep a high wire tension of a part for cutting a workpiece while suppressing the deformation of a delivery member and a winding member allowing a wire to be wound around them to ensure high machining precision by a simple configuration.

In these wire saw and cutting method, a workpiece 28 is cut by feeding it to many wires W wound around guide rollers 24A, 24B, 26A, 26B. Each of main motors 25A, 25B is connected to the guide rollers 26A, 26B to give a difference in roller drive torque generated by both main motors 25A, 25B so that a tension of a wire part between the guide rollers 24A and 24B is locally increased and the workpiece 28 is fed to this part for cutting.