Provided is a medical wire including: a main wire-strand portion that is formed of a plurality of main wire strands and that extends over the entire length of the medical wire; and at least one sub wire-strand portion that is disposed at an outer circumference of the main wire-strand portion, that is secured to the main wire-strand portion, and that is formed of a sub wire strand, wherein the diameter of the sub wire strand is at least twice the diameter of the main wire strand, and a first region having a relatively small lateral cross-sectional area and a second region having a lateral cross-sectional area that is greater than that of the first region are included.