To prevent the rotation of a rotary die even when an external force is added to the rotary die from the outside during press forming.

The rotary die 4 is rotatably provided in the cavity 2 of a lower die 1, a metal plate 3 is press-formed between the lower die 1 provided with the rotary die 4 and an upper die 6 and, after that, the rotary die 4 is separated from the metal plate 3 by rotating the rotary die 4 by a specified angle with a cylinder device 5. A horizontal supporting surface 8 and vertical supporting surface 7 for supporting the rotary die 4 at press forming are provided at the inside surface of the cavity 2. A press-contact member 20 of the rotary die connected with the driving shaft 5a of the cylinder device 5 is arranged on the sliding surface 2a of the inside surface of the cavity 2. This press-contact member 20 is provided with the press-contact parts 24 and 25 for press-contact and rotating the rotary die 4 by the specified angle by the advancing and retreating operation of the driving shaft 5a and provided with the horizontal supporting surface 21 for supporting the rotary die 4 at press forming and obstructing the rotation of the rotary die 4.