The magnet cutting device includes a pair of supporting portions spaced apart by a predetermined distance and configured to support the magnet from a bottom side, a blade configured to press the magnet supported by the pair of supporting portions from an upper side of the magnet, and a magnet supporting tool arranged between the pair of supporting portions to support the magnet from the bottom side of the magnet. A surface of the magnet supporting tool to be held in contact with the magnet is shaped such that a central part of an upper end is higher than the upper ends of the pair of supporting portions and an end part of the upper end is lower than the upper ends of the pair of supporting portions when the magnet is placed on the surface, the upper end having a slope connecting the central part and the end part.