  The dual Meissner effect is the promising mechanism for quark confinement. We
have proposed a new formulation of SU(N) Yang-Mills (YM) theory on a lattice,
which can extract the dominant mode for quark confinement in the gauge
independent manner. In the last lattice conference, we have demonstrated by
measuring the string tension from the Wilson loop average in the SU(3) YM
theory that the restricted non-Abelian variable and the extracted non-Abelian
magnetic monopoles play the dominant role in confinement of fundamental quarks
(dominance in the string tension), in marked contrast to the Abelian
projection.
  In this talk, we focus on the dual Meissner effect in SU(3) YM theory, which
is examined by measuring the distribution of chromo-electric field strength
created by a static quark-antiquark pair. We apply the new lattice formulation,
and examine whether or not the non-Abelian dual superconductivity claimed by us
is indeed a mechanism of quark confinement. We present a preliminary result of
the direct evidence for the non-abelian dual Meissner effect, that is to say,
restricted U(2)-field part of the flux tube plays the dominant role in the
quark-antiquark potential.
