In a game machine which comprises a roulette part for rotating an indicating mark along an outside of a play field, the indicating mark is stopped in accordance with a signal from a stop switch. If the indicating mark is stopped in a center position of a prize area which is indicated with a chance gage, a payment of medals as a reward is allowed. If the indicating mark is stopped in a position which is included in the prize area but don't coincide with the center position, a process of a lottery with a random number is carried out and a gage volume of a level gage is changed in the basis of the random number. An additional chance of a payment of medals is given corresponding to a position in which the indicating mark is stopped.