  In the framework of the two-form gravity, which is classically equivalent to
the Einstein gravity, the one-loop effective potential for the conformal factor
of metric is calculated in the finite volume and in the finite temperature by
choosing a temporal gauge condition. There appears a quartically divergent term
which cannot be removed by the renormalization of the cosmological term and we
find there is only one non-trivial minimum in the effective potential. If the
cut-off scale has a physical meaning, \eg the Planck scale coming from string
theory, this minimum might explain why the space-time is generated, \ie why the
classical metric has a non-trivial value.
