PURPOSE: To eliminate the interference of an electrical driving source which drives an opening/closing member when setting a prize ball path arranged at the rear plane side of a game panel by comprising a flexible prize device by arranging by almost adhering on the rear plane side of a mounting substrate, and forming with the electrical driving source which drives the opening/closing member.

CONSTITUTION: The flexible prize device 30 whose rear plane is closed with a cover plate 53 is mounted on the surface of the game panel 9 by inserting to a mounting hole opened at the game panel from the front of the game panel 9, and after that, screwing with a screw in the mounting hole 57 formed appropriately on the outer periphery of the mounting substrate 31. Since solenoids 50a, 50b that is the electrical driving source which drives the opening/closing members 33a, 33b are arranged adhesively at the rear plane side of the mounting substrate 31 mounted on the surface of the game panel 9, it follows that all the solenoids 50a, 50b are located in the thickness of the game panel 9 when the flexible prize device 30 is loaded on the game panel 9, and it is scarcely protruded to the rear plane side of the game panel 9. In such a way, it is possible to prevent the prize ball path 21 arranged at the rear plane side of the game panel 9 interfered by the solenoids 50a, 50b.