AbstractMagnetic fields (MF) can play an essential role in the evolution of the interstellar medium - especially at the early evolutionary stages. Small scale research related to the interaction of MF and pre-stellar condensations are unresolved issues. In quantitative terms, submissions about forming a full picture of gas-dust fragments evolution are far from complete, considering delay of their collapse caused by MF and the reverse effect of self-gravitating objects on the transformation of force lines and changing the values of local strength. The role of these interrelated processes is very important in the estimation of time of evolution of protostellar structures. In contrast to OH, in methanol molecule (most investigating at the moment) there is no unpaired electron, and the Zeeman splitting of the energy levels in CH₃OH regards only the levels caused by the nuclear spin. Therefore, Zeeman spectrum in methanol is certainly not going to be as effective as in OH. However, since many methanol masers - Class I (MMI - formed at the earliest stage of the evolution of gas and dust condensations) and Class II (MMII - the area around very young stars and protoplanetary disks) - are associated with OH masers, then from spectra of OH masers the parameters of MF can be estimated, at least, near different methanol masers classes, i.e. in condensations which are at different evolutionary stages. This report presents the results of polarization observations 7 OH maser sources at the NRT (France). The main goal is comparing similarities and differences in MF strength and orientation in these masers, which essentially different according to the type of methanol masers associated with them, i.e. the evolutionary type.