To increase expectations for a special game state in the variable display of identification information in a special mode in which it is impossible to specify control to the special game state, and to increase player's attention even to the variable display not to be a specified game result.

A performance mode is controlled to a probability variable latent mode in which it is impossible to specify whether or not control to a probability variable state is executed always after the end of a big winning game state based on a probability variable latent big winning accompanied by a shift to the probability variable state and at a fixed rate after the end of a big winning game state based on a time shortening big winning not accompanied by the shift to the probability variable state. The big winning symbols of a probability variable big winning for establishing the control to the probability variable state are in the display form of arranging three symbols of a specified kind. The rate of displaying the ready-to-win display form of displaying two symbols of the specified kind among the display of the ready-to-win display form is higher when the control to the probability variable state is executed than that when the control is not executed.

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