To provide a manufacturing method and a manufacturing device in which a stacked iron core excellent in shape precision can be manufactured by applying a rotatably stacking means without causing a trouble of shape deterioration by stacking displacement, even when rotatably stacked iron core pieces are the ones used for a stepping motor.

In the manufacturing method of the stacked iron core 1, iron core pieces 10 are formed from a processed plate "t" by press working and punched into a die 6 by a punch 8. The die 6 is rotated with an iron core 1a stacked earlier. Then, the punched iron core pieces 10 are stacked on the rotated iron core 1a by caulking via caulking portions "k". The iron core 1a punched earlier and stacked in the die 6 is fixed immovably in the direction of rotation of the die by forming a shape of the inside circumferential surface 6n of the die 6, rotated with the die 6 at the same rotation angle with that of the die 6, and then the punched iron core pieces 10 are stacked by caulking.