A manufacturing device for cleft magnets comprises a cleaving mechanism for cleaving a magnet plate by applying a pressing force to the magnet plate corresponding to a back of a groove formed on one surface of the magnet plate and a carry-in mechanism for carrying the magnet plate to a cleaving position by the cleaving mechanism. By comprising a foreign matter removal mechanism for removing a foreign matter adhering to the magnet plate before the magnet plate is carried to the cleaving position by the carry-in mechanism, the foreign matter adhering to the magnet plate is removed before cleaving.
