The present utility model discloses an electric tinfoil-cutting device for automatic corkscrews, which comprises a reduction gearbox, a driving motor, a movable support and a blade assembly comprising a blade-mounting carrier and blade-mounting blocks, wherein the movable support are provided with support limit projections which are embedded in mounting carrier limit notches of the blade-mounting carrier, each of the blade-mounting blocks comprises a horizontal mounting block portion and a vertical mounting block portion, and a tinfoil-cutting blade is mounted on the vertical mounting block portion. The electric tinfoil-cutting device of the present utility model can achieve an automatic tinfoil-cutting function and has the advantages of novel structural design, high degree of automation, and convenience in use.