  Using the PCAC relation, we derive a compact formula for the pion decay
constant $F_{\pi}$ in the nonlocal chiral quark model. For practical
calculations this formula may be used both in the Minkowski and in the
Euclidean space. For the pion momentum $P_{\mu}\to0$ it reduces to the well
known expression derived earlier by other authors. Using a generalized dipole
Ansatz for the momentum dependence of the constituent quark mass in the
Minkowski space, we express $F_{\pi}^{2}$ in terms of a single integral over
the quark momentum fraction $u$. We interpret the integrand as a pion
distribution amplitude $\phi(u)$. We discuss its properties and compare with
the $\pi$DA's obtained in other models.
