  We consider the Darboux transformation of the Green functions of the regular
boundary problem of the one-dimensional stationary Dirac equation. We obtained
the Green functions of the transformed Dirac equation with the initial regular
boundary conditions. We also construct the formula for the unabridged trace of
the difference of the transformed and the initial Green functions of the
regular boundary problem of the one-dimensional stationary Dirac equation. We
illustrate our findings by the consideration of the Darboux transformation for
the Green function of the free particle Dirac equation on an interval.
