A guidewire includes a core shaft having a tip portion and a rear end portion, and a hollow stranded-wire body formed by twisting a plurality of strands. The core shaft includes a small-diameter portion including the tip portion and extending over a predetermined area from the tip portion toward the rear end portion, and a large-diameter portion located nearer to the rear end portion than the small-diameter portion and extending over a predetermined area in the direction from the tip portion toward the rear end portion. The small-diameter portion is inserted into the hollow stranded-wire body and covered with the hollow stranded-wire body to partially constitute an outer circumferential surface of the guide wire.
