To downsize the role object of a start winning port in a vertical direction compared to the case of using a tulip type role object provided with an introduction part and two blades.

The start winning port 10 is formed on a game board 4, and the start winning port 10 having the opening width of roughly 50 mm is formed. An introduction role object 20 is attached to the front surface side of the start winning port 10, and the introduction role object 20 is provided with an opening/closing door 21 and a ball receiving part 22. The opening/closing door 21 and the ball receiving part 22 are integrally formed. The opening/closing door 21 is provided so as to be turned between an open position at which it opens the start winning port 10 and a closed position at which it covers the start winning port 10. The ball receiving part 22 is shifted to the side of a turning shaft 21b which is a pivotally supporting part of the opening/closing door 21 and formed so that the bottom surface of the ball receiving part 22 roughly matches with the bottom surface of the opening/closing door 21. A door hole 21a is formed on the opening/closing door 21 and an introduction passage 22a is formed on the ball receiving part 22 respectively. The entrance 22b of the introduction passage 22a having the opening width of roughly 15 mm is formed.