To provide a group roller driving method for a wire saw and its device wherein the tension of a wire at the cutting process portion of a wire saw is stabilized, and the waviness and roughness of a cutting plane is made low.

The value of current flowing to the motor 31 of a group roller 21 is detected so as to be added to and multiplied with a constant value set in advance, and a value obtained as a result of the aforesaid operation is outputted to a second motor control device 133 as a motor current commanding value. By this constitution, since the difference in torque between the group roller 21 and a group roller 22 is thereby stabilized, optimum tension can be applied continuously to a wire row 24 to be used for a cutting process at all times, so that an excellent cutting plane can thereby be obtained.