  The contributions of the matter superfields and of the Faddeev--Popov ghosts
to the $\beta$-function of ${\cal N}=1$ supersymmetric gauge theories defined
in terms of the bare couplings are calculated in all orders in the case of
using the higher covariant derivative regularization. For this purpose we use
the recently proved statement that the $\beta$-function in these theories is
given by integrals of double total derivatives with respect to the loop
momenta. These integrals do not vanish due to singularities of the integrands.
This implies that the $\beta$-function beyond the one-loop approximation is
given by the sum of the singular contributions, which is calculated in all
orders for singularities produced by the matter superfields and by the
Faddeev--Popov ghosts. The result is expressed in terms of the anomalous
dimensions of these superfields. It coincides with the corresponding part of
the new form of the NSVZ equation, which can be reduced to the original one
with the help of the non-renormalization theorem for the triple gauge-ghost
vertices.
