In a gaming system, a part of a bet is accumulated in a progressive bonus counter in a case of executing a slot game in each of slot machines. Then, in a case where an accumulated count value of the progressive bonus counter has reached a predetermined value, an event game which the plurality of slot machines participate in is executed, and a progressive bonus corresponding to a part or entirety of the accumulated count value is provided to a player who has won the event game. Moreover, in a case where the accumulated count value of the progressive bonus counter has reached the predetermined value when the slot game is being executed only in one slot machine, a mystery bonus is generated. Accordingly, a profit can be returned to players who execute the slot game.