The advantageous points of ERG in applications to non-perturbative analyses
of quantum field theories are discussed in comparison with the Schwinger-Dyson
equations. First we consider the relation between these two formulations
specially by examining the large N field theories. In the second part we study
the phase structure of dynamical symmetry breaking in three dimensional QED as
a typical example of the practical applications.Comment: 13 pages, 6 figures, references are added. Invited talk presented at
Second Conference on the Exact RG, Sept 18 - 22, 2000, Rome, Ital
