To prevent fraudulent operation using a clearance between a ball lending machine and a game machine arranged in a game island.

A single outside frame 21 in put between two ball lending machines 10, which are installed to the island 1 at an interval allowing storage of a single game machine 20, to be fixed to the island 1, and a clearance D formed between the ball lending machine 10 and the outside frame 21 is sealed by means of a sealing member 15 arranged in the ball lending machine 10. When a hinge of a front frame 27 carrying all the mounted parts necessary for a game is fitted to a hinge 25 of an outer frame 21 from the front side, the front frame 27 is assembled to the outer frame 21 to be opened forward on one side in the lateral direction, thus constituting the game machine 20. In this condition, a fraudulent operation member F inserted from the clearance D collides against the sealing member 15 and prevented from entering further.