The spectra of secondary neutrons produced in the interaction of 4.92-and 5 74-MeV neutrons with fissile nuclei Pu-239 have been measured by the time-of-flight method in cylindrical geometry at angles 45-degrees, 60-degrees, 90-degrees, 120-degrees, and 150-degrees. Double differential cross sections for elastic and inelastic scattering of neutrons have been obtained from the experimental results.