  We study the dynamics of SU(2) gauge theory with NF=6 Dirac fermions by means
of lattice simulation to investigate if they are appropriate to realization of
electroweak symmetry breaking. The discrete analogue of beta function for the
running coupling constant defined under the Schroedinger functional boundary
condition are computed on the lattices up to linear size of L/a=24 and preclude
the existence of infrared fixed point below 7.6. Gluonic observables such as
heavy quark potential, string tension, Polyakov loop suggest that the target
system is in the confining phase even in the massless quark limit.
