The order parameters of each component in a binary mixture consisting of substances exhibiting a nematic phase and an isotropic phase have been evaluated by Monte Carlo simulation using the method of Vacatello and Iovino based on the Flory-Ronca-Irvine mean field theory. An induction of ordering for an isotropic solute has been obtained in the nematic phase. The degree of induction is dependent not only on the parameters of the interactive orientational potential but also on the anisotropy of the molecular shape of the isotropic solute.