Аннотация:A novel quantum field-theoretical approach to describing the processes passing at finite distances and finite time intervals, to which belong, in particular, neutrino oscillations, is put forward. It makes use of only the neutrino mass eigenstates, while the flavor states are not needed. It is shown that the approach allows one to consistently describe neutrino oscillations using only plane waves. The advantages of the approach are its extreme similarity to the standard Feynman diagram technique, the physical clearness and technical simplicity.