PURPOSE: To provide a self-anticorrosive function to a clamping member made of iron such as a bolt when the member is used in seawater, etc. and to prevent the formation of rust by attaching a different metal having a higher ionization tendency than iron to the member.

CONSTITUTION: Holes 2 are bored in a clamping member 1 made of iron such as a bolt, a nut or a washer, and an inexpensive metal aush as Al or Zn, or an alloy 3 of such metals or such a metal and Mg having a higher ionization tendency than iron is filled into the holes 2 as galvanic electrodes. The member 1 may be further plated with Zn or the like 4 as required. Even if the resulting member is used in an electrolyte soln. such as seawater for a long term, it has a self-anticorrosive function due to the galvanic electrodes and prevents the formation of rust.