To provide a cutting method using a wire saw capable of achieving the shortening of a cutting time without lowering the cutting efficiency of the wire saw even in a case that a material part having higher hardness is contained in a part of the cutting surface of a cutting target.

A through-hole 2 is formed to the cutting target so as to divide the cutting scheduled surface 1 set to the cutting target into a plurality of parts and the wire saw 3 is inserted in the through-hole 2 while the wire saw 3 exposed from the through-hole 2 is stretched over a running auxiliary device 4 in a runnable manner so as to go toward the outer edge of the cutting scheduled surface 1. The wire saw 3 is driven and run to cut a plurality of dividing and cutting scheduled surfaces 1a and 1b in parallel by the range 3a of the wire saw exposed from the through-hole 2 and the range 3b of the wire inserted in the through-hole 2 to cut the cutting target.