The present invention is a method for manufacturing a wire saw apparatus that has a wire supply reel, a long roller, wire guides, a wire winding reel, and a tension arm that is controlled so as to operate within a set control angle +/-A (degrees) and is for applying tension on the wire. The method for manufacturing a wire saw apparatus comprises: a step for measuring the surface roughness Rmax ofthe long roller; a step for measuring, while extending the wire from the wire supply reel, the angle a (degrees) of the tension arm when the angle of the tension arm swings outside of the set range for the set control angle; a step for calculating a formula shown in the description when the measured long roller surface roughness Rmax is R1 ([mu]m); and a step for making the long roller surface roughness Rmax to be the calculated numerical value R2 or less. Provided thereby is a method for manufacturing a wire saw apparatus that is able to keep the tension arm from swinging widely outside of the control range.