Abstract: A wire saw apparatus which improves the flatness of cut work and reduces the wire disconnection occurrence rate, is disclosed. The wire saw apparatus comprises: a wire supply part for supplying a cutting wire to a cutting part, which includes a wire supply reel bobbin; the cutting part for cutting a work, including a roller with grooves around which the cutting wire is wrapped; and a wire take-up part for taking up the cutting wire from the cutting part, which includes a wire take-up reel bobbin; wherein the dynamic balance of each of the wire supply reel bobbin, the roller with grooves, and the wire take-up reel bobbin is taken so that the quantity of unbalance thereof is not larger than 5 g.multidot.cm.