To provide a method of manufacturing a core for a dynamo-electric machine and a core plate punching device, whereby the core plate can be accurately positioned and laminated on the adjoining core plate in the laminating direction when punching out the core plate with the end fringe parts of a magnet holding hole on the outer peripheral side and the inner peripheral side of the core plate separated from each other.

Core plates 12, 13 having magnet holding holes 15 are punched from a strip-shaped work W by a die 22 and a punch 23, and the core plates 12, 13 are laminated to manufacture the core for the dynamo-electric machine. When punching the core plates 12, 13, prior to punching, the inside fringe part of the magnet holding hole 15 on the outer peripheral side of the core plate is pressed down by a pressing part 26 provided in the punch 23. Simultaneously with punching of the core plates 12, 13, the outside portion of the magnet holding hole 15 is conjoined to the outside portions of the core plates 12, 13 adjoining in the laminated direction at a dowel 18 by a protrusion 27 provided in the punch 23.