Abstract: A game machine has an input section through which a player inputs various instructions necessary for the play. The input section also displays various kinds of game information and performs computation of the score. The machine also has a mechanical section which includes a tank having a transparent wall and filled with water, a plurality of balls suspended in the water, a central tubular structure for creating a central upward flow of water, a liquid supply portion including a nozzle under the tubular structure, and an information reading unit disposed in a peripheral region of the tank through which the balls fall down due to, for example, difference in the specific gravity between the ball and the water. A rotary guide rail is disposed in the peripheral region so as to catch the falling balls.