The positions of neutron resonances have been shown to be highly sensitive to the variation of fundamental nuclear constants. The analysis of the measured isotopic shifts in the natural fossil reactor at Oklo gives the following restrictions on the possible rates of the interaction constants variation: strong ~2x10-19 yr-1, electromagnetic ~5x10-18yr-1, weak ~10-12yr-1. These limits permit to exclude all the versions of nuclear constants contemporary variation discussed in the literature.