The present invention is a wire saw in which a wire is wound around a plurality of grooved rollers, the workpiece is sliced into wafers by causing the wire to travel and pressing the workpiece against the wire while a slurry is supplied to the grooved rollers, the wire saw controlling in such a manner that the workpiece is sliced while a supply temperature of the slurry is increased from the start to the end of slicing the workpiece. As a result, there is provided a wire saw in which Warp of the workpiece to be sliced can be improved by suppressing a decrease in a temperature of the workpiece in the vicinity of the slicing end portion of the workpiece and by making an increase in displacement of the grooved roller during slicing straight, that is, by making the slicing trajectory depicted in the workpiece close to a straight line.