[en] Characteristics of the fissile isomer are determined and its yield in the ²³⁸U(n,n')n reaction at the neutron energies ranging from 2.5 to 4.7 MeV is measured. The measurements have been done on a pulsed electrostatic accelerator. To determine an isomer half-life, use has been made of a delayed fission spectrum. An isomer half-life is equal to 300+-32 ns. The threshold for the isomer production is found to be 2.7+-0.15 MeV. The isomer yield with respect to that of prompt fission neutrons at the energy ranging from 2.9 to 4.7 MeV is about 2x10^-4. An attempt is made to calculate the cross section of isomer production, assuming that the four-quasiparticle 2p, 2n state is an isomeric one