The deposition behavior of the electroless nickel plating in the nm order region was examined using optical fiber probe for a near-field optical microscopy. A tip part of optical fiber probe is about tens of nm. In such a minute area, initiation of nickel deposition reaction is difficult. However, the deposition reaction is started by the increment of the adsorbed amount of palladium on to a minute region. In addition, the diameter of aperture without nickel deposition on the tip can be controlled by the addition of various stabilizers to the plating bath. The minute probe of aperture diameter about 50nm was obtained by the addition of 100ng/dm3 of bismuth ion in the plating bath and operated at pH 6.0 for 15 minutes.
