  The nontrivial boundary conditions for the Topcolor breaking are investigated
in the context of the TeV-scale extra dimension scenario. We present a six
dimensional model where the top and bottom quarks in the bulk have the Topcolor
charge while the other quarks in the bulk do not. We also put the electroweak
gauge interaction in the six dimensional bulk. Then the bottom quark
condensation is naturally suppressed owing to the power-like running of the
bulk $U(1)_Y$ interaction, so that only the top condensation is expected to
take place. We explore such a possibility based on the ladder Schwinger-Dyson
equation and show the cutoff to make the model viable.
