  Finite temperature transition in lattice QCD with degenerate Wilson quarks is
investigated on an $N_t=4$ lattice, using a renormalization group improved
gauge action. We find the following for the $N_F=2$ case:
  1) The transition is smooth for a wide range of the quark mass.
  2) The chiral transition is continuous.
  3) The chiral condensation well satisfies a scaling relation with the
critical exponents of the 3 dimensional $O(4)$ spin model. For $N_F=3$, we find
that the chiral transition is of first order.
