A novel electron spectrometer has been designed to study low-voltage field-induced emission of nanostructures such as nanoporous carbon, nanotubes, nanodiamond and other carbon structures. The estimated high resolving power of the device is mainly achieved by using an original energy analyzer of high energy dispersion and by retarding the electron beam by the factor of tens and hundreds in terms of energy. The analyzer pass energy governs the absolute energy resolution ΔЕ of the spectrometer; ΔЕ value varies approximately in the range of 10meV<ΔЕ< 300meV. There are three different working modes adapted for emission of widely variable current. The minimal emission current at which energy analysis is still possible is approximately 0.1nA. The spectrometer working modes were tested experimentally using a thermoemitter as the test object. The study then proved that the recorded spectra reflected physical phenomena taking place on the emitter surface.