In a medical guide wire (1), a rigid portion (4A) is located at
a distal end of a helical spring (4), and the rigid portion (4A)
measures 0.5 mm or less which extends from a top end of a head plug (5)
to a rear end of a portion in which the helical spring (4) is secured to
the head plug (5), and an intermediary location (11) is secured to
an intermediary boss portion (9) of a core line (3) to provide a
loosely wound portion (8) from a rear end of the head plug (5) to
the intermediary location (11) to be elastically expandable due to a clearence
(C) appeared between line element turns of the loosely wound portion (8).
