Provided is a guide wire having a novel structure, with which it is possible to improve production efficiency and to effectively prevent large irregularities from forming on an outer circumferential surface of a core wire. Further provided is a guide wire having a novel structure, with which it is possible to more meticulously set bending rigidity to a distal end portion thereof. In a guide wire having a coil externally mounted about a distal end portion of a core wire, a proximal end portion of the coil is integrally joined to the core wire during formation of the coil. Furthermore, in a guide wire having a coil externally mounted about a distal end portion of a core wire, a cross-sectional shape of a wire that constitutes the coil varies in a lengthwise direction of the coil.