A guide wire includes an elongated main body possessing flexibility. The main boy is comprised of a first wire having a core member constituted by a metal material, a second wire having a core member arranged on the proximal side of the first wire and constituted by a metal material, and an optically transmissive member arranged between the first wire and the second wire, and connecting the first and second wires to each other and constituted by a substantially transparent tube shaped body. The optically transmissive member exhibits light permeability such that when light is illuminated from one direction of a lateral side thereof, the light is transmissible to the opposite side through the center axis of the main body.