  There are supersymmetric gauge theories which do not possess any parameters
nor flat directions, and hence cannot be studied anywhere in the field space
using holomorphy (``non-calculable''). Some of them are believed to break
supersymmetry dynamically. We propose a simple technique to analyze these
models. Introducing a vector-like field into the model, one finds flat
directions where one can study the dynamics. We unambiguously show that the
supersymmetry is broken when the mass of the vector-like field is small but
finite, and hence Witten index vanishes. If we increase the mass of the
vector-like field, it eventually decouples from the dynamics and the models
reduce to the original non-calculable models. Assuming the continuity of the
Witten index in the parameter space, one can establish the dynamical
supersymmetry breaking in the non-calculable models.
