On the Lebesgue Inequality on Classes of \bar{\psi} -Differentiable Functions

We consider the deviations of Fourier sums in the spaces $ {C^{\bar{\psi}}} $ . The estimates of these deviations are expressed via the best approximations of the $ \bar{\psi} $ -derivatives of functions in the Stepanets sense. The sequences $ \bar{\psi} $ = (ψ1, ψ2) are quasiconvex.