A medical guide wire which has a core wire having a distal end-side small-diameter portion and a proximal end-side large-diameter portion having a larger outside diameter than the outside diameter of the distal end-side small-diameter portion, and a coil spring installed on an outer periphery of the distal end-side small-diameter portion of the core wire along an axial direction and fixed to the core wire at at least the front end portion and rear end portion thereof. The outside diameter of the proximal end-side large-diameter portion of the core wire and the outside diameter of coil of the coil spring are each at most 0.012 inch. The front end portion of the coil spring is fixed to the core wire by gold-containing solder. The length of a distal end portion stiffened by the gold-containing solder is 0.1 to 0.5 mm. The medical guide wire is high in fixing strength of the coil spring to the core wire and can shorten a shaping length compared with a conventional medical guide wire.