To provide a device cutting an object to be cut by a wire saw, which realizes compact, lightweight, low-noise, and high-performance design.

A driving system comprising a driving pulley 12 is mounted on a strut supported on a base stand. The driving pulley 12 comprises a stator 21 as a fixed shaft, a ring-shaped rotor 22 arranged on a periphery of the stator 21, and a ring-shaped pulley 29 arranged on a periphery of the rotor 22. On a channel 28 formed on a periphery of the pulley 29, a wire saw 5 which is provided with a ring part 5a sintering a diamond abrasive grain is arranged to be wound. When the driving pulley 12 is energized, the rotor 22 is rotated and driven so as to run the wire saw 5 wound around the pulley 29 and cut the object to be cut which is wound by contacting the wire saw 5.