A new method for determining the angular and energy distributions of an anisotropic fast-neutron flux by using nuclear emulsions based on the proton-recoil method is proposed. The relation between the distributions of neutron flux and proton-recoil tracks is analyzed, and formulas for obtaining the angular distribution and energy spectrum of the neutron flux from the measurement of proton-recoil tracks are derived. Measurements were made to investigate the accuracy of this method with the emulsion plate, which was irradiated inside a natural uranium system. The experimental results show that the measurement of the anisotropic component, which hitherto could not be measured, is possible.