A medical guide wire includes a flexible long core. A core elongated component is disposed to extend forwards from the core, and has a tapered shape. A helical coil is disposed about the core elongated component, secured by attachment of a coil distal end and a coil proximal end to the core elongated component. The helical coil includes an equiradial coil portion having the coil proximal end, disposed at a portion of the core elongated component on a side of the core. A diameter decreasing coil portion has the coil distal end, extends forwards from the equiradial coil portion, has a decreasing diameter, and has a length 25 mm or more. A diameter ratio D1/D2 of the diameter decreasing coil portion is 1.22-2.31, where D1 is a proximal end diameter of the diameter decreasing coil portion, and D2 is a distal end diameter of the diameter decreasing coil portion.