  The baryogenesis is reanalyzed based on the model by A.G.Cohen et al., in
which the lepton number, generated by the neutrinos' scattering from the bubble
walls appearing in the development of the electroweak phase transition, is
converted to the baryon number excess through the sphaleron transition. A
formula obtained in this paper on the lepton number production rate is correct
for the both thin and thick walls within the linear approximation.
Investigation on the time-development of the first order phase transition is
simulated, including the temporal change of the wall velocity as well as the
fusion effect of the bubbles. The details of such phase transition dynamics are
found to affect considerably the final value of the baryon number excess.
