  The gluon fields screening in the stochastic vacuum of gluodynamics is
studied. The effective action is derived for the instanton interacting with
nonperturbative fields. Quantum nonperturbative effects are shown to affect
greatly the shape of instanton. The power asymptotics x^{-2} of the classical
"instanton's profile function" at large distances is replaced due to yhese
effects by Airy function asymptotics x^{-1/4} exp(-const\cdot x^{3/2}).
