To provide a guide wire which has X-ray contrast properties as well while having a visible mark (visible marker).

The guide wire has a core material, a plastic coating added with coloring agents covering at least a portion of the core material and made color developable by a laser, the visible marker by color development of the coloring agents disposed on the prescribed area of the surface of the plastic coating and the X-ray contrast portion making contrast imaging by X-rays possible on at least a portion of the outer periphery of the core material, by which the X-ray contrast imaging is made possible. In addition, the position of the guide wire can be endoscopically checked by the visible marker formed by the color developing agents.