The electromagnetic radiative correction to the cross section of the vector
meson electroproduction is calculated. Explicit covariant formulae for the
observed cross section are obtained. The dependence of the radiative correction
on the experimental resolution and on the inelasticity cut is discussed.
FORTRAN code DIFFRAD based on both exact (ultrarelativistic) and approximate
sets of the formulae for the radiative correction to the cross section is
presented. The detailed numerical analysis for kinematical conditions of the
recent experiments on the diffractive electroproduction of vector mesons is
given.Comment: 7 pages, 9 figure