The invention relates to a nanofiber web preparing apparatus and method via electro-blown spinning. The nanofiber web preparing method includes feeding a polymer solution, which is a polymer dissolved into a given solvent, toward a spinning nozzle, discharging the polymer solution via the spinning nozzle, which is charged with a high voltage, while injecting compressed air via the lower end of the spinning nozzle, and collecting fiber spun in the form of a web on a grounded suction collector under the spinning nozzle, in which both of thermoplastic and thermosetting resins are applicable, the solution does not need to be heated and electrical insulation is readily realized.