To provide a coil body that has high flexibility, satisfactorily tracks a complicated shape, and remarkably transmits fine vibrations occurring on a part of the coil body, and a guide wire using the coil body. A coil body 1 is formed by helically winding a stranded wire 11 including a plurality of stranded element wires. The stranded wire 11 has a first gap as a hollow at the center of the stranded wire.
