  The amplitudes of $\pi$-meson decays are calculated in a relativistic
nonperturbative quark model which assumes that mesons are made of a quark
antiquark pair and of a scalar neutral component representing the contribution
of the nonelementary fluctuations of the quark gluonic field. The experimental
data can be fitted in a satisfactory manner using current quark masses
$m_u\approx1.5\ MeV, m_d\approx9\ MeV$.
