A wire saw apparatus including: a plurality of wire guides; a wire row formed of a wire which is wound around the plurality of wire guides and configured to reciprocatively travel in an axial direction; a nozzle configured to supply a coolant or slurry to the wire; a workpiece-holding portion configured to suspend and hold a workpiece plate having a workpiece bonded thereto with a beam interposed therebetween; a workpiece-feeding mechanism configured to press the workpiece against the wire row; and a mechanism configured to adjust a parallelism of axes of the plurality of wire guides around which the wire row is formed. Thereby, a wire saw apparatus and a method for manufacturing a wafer are provided which enable manufacturing of a wafer having any warp shape by controlling a warp in a wire travelling direction of a sliced workpiece.