A processor selects either a first game mode or a second game mode based on the operation by the operator carried out at a server 102. If the first game mode has been selected, a payout is calculated and awarded based on a fixed payout set in advance for each winning combination. Alternatively, if the second game mode has been selected, a payout is calculated and awarded based on a progressive payout and a fixed payout which was set in advance for each winning combination.