Patent Publication Number: US-2009239616-A1

Title: Slot Machine Capable Of Changing Odds And Control Method Thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of priority based on US Provisional Patent Application No. 61/038,505 filed on Mar. 21, 2008. The contents of this application are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a slot machine capable of changing odds and a control method thereof. 
     2. Discussion of the Background 
     In conventional slot machines, when a player inserts game media such as medals, coins or bills into an insertion slot of the slot machine and presses a spin button, then a plurality of symbols are scroll-displayed to a display portion provided on the front surface of a casing and, thereafter, the respective symbols are automatically stopped, as disclosed in U.S. Pat. Nos. 6,960,133, 6,012,983 and 6,093,102. In this case, when scroll-display of respective symbols starts by an input from the spin button, symbols are selected using random numbers, and the selected symbols are stop-displayed to the display portion. Then, when a combination of the stop-displayed symbols along a winning line is a predetermined winning combination (prize), a payout is conducted. 
     Further, among conventional slot machines, there are some slot machines which conduct two types of payouts which are a payout determined according to the combinations of symbols rearranged along winning lines and a payout determined according to the number of displayed scatter symbols, as disclosed in U.S. Pat. No. 6,604,999 and US 2002-0065124-A1. In such a slot machine which conducts payouts based on such scatter symbols, there is no relationship between payouts and positions at which the scatter symbols are displayed. 
     In such a conventional slot machine, in general, odds are preliminary determined for each type of prizes. In the present description, odds show a relation between the type of the prize and an amount of game media to be paid out in the case of establishment of the prize. For example, in many slot machines, a number of a coin to be paid out based on the establishment of a prize in the case that the prize is established when a single coin is BET (number of payouts per single coin) is determined for each type of the prizes. 
     However, since such odds are generally not changed during the game, there has been a problem that the player may be tired of the game while playing the game with fixed odds. 
     In light of the aforementioned problem, the present invention has been devised, and an object of the present invention is to provide a slot machine capable of changing odds and a control method thereof. 
     The contents of U.S. Pat. No. 6,960,133, U.S. Pat. No. 6,012,983, U.S. Pat. No. 6,093,102, U.S. Pat. No. 6,604,999 and U.S. 2002-0065124-A1 are incorporated herein by reference in their entirety. 
     SUMMARY OF THE INVENTION 
     The present invention provides a slot machine having the following configuration. 
     That is, the slot machine comprises: a symbol display capable of variably displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds; and a controller. The controller is programmed to execute processing of (A) stop-displaying the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, (B) determining an amount of payout based on normal odds indicating a relation between the stop-displayed normal symbol and the amount of payout and on the normal symbol stop-displayed in the processing (A), (C) determining, when the odds-change symbol has been stop-displayed in the processing (A), the amount of payout based on special odds different from the normal odds and on the normal symbol stop-displayed in the processing (A), instead of executing the processing (B), in a game subsequent to the game in which the odds-change symbol has been stop-displayed, and (D) paying out a game medium in the amount of payout determined in any one of the processing (B) and the processing (C). 
     According to the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined based on the special odds different from the normal odds, in the game subsequent to the game in which the odds-change symbol has been stop-displayed. Namely, the odds are changed. 
     As thus described, according to the slot machine, the odds are changed as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the change of the odds and thus fully enjoy the game. 
     Further, since the odds are changed in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, the processing (C) is processing of determining, when a number of the odds-change symbol stop-displayed in the processing (A) satisfies a predetermined condition, the amount of payout based on the special odds and on the normal symbol stop-displayed in the processing (A), in the game subsequent to the game in which the number of the odds-change symbol stop-displayed has satisfied the predetermined condition. 
     According to the slot machine, the odds are changed in the case that the number of the odds-change symbol stop-displayed satisfies the predetermined condition. Accordingly, whether or not the number of odds-change symbol satisfies the predetermined condition, namely, how many odds-change symbols are stop-displayed is of great concern for the player. Therefore, it is possible to have the player find great pleasure in counting the number of the odds-change symbol while playing the game. Consequently, it is possible to have the player fully enjoy the game. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, the processing (C) is processing of determining the amount of normal payout based on the special odds corresponding to the number of the odds-change symbol stop-displayed in the processing (A) and on the normal symbol stop-displayed in the processing (A). 
     According to the slot machine, in the case that the number of the odds-change symbol stop-displayed satisfies the predetermined condition, the odds in the game subsequent to the game in which the number of the odds-change symbol stop-displayed has satisfied the predetermined condition are changed to the special odds corresponding to the number of the odds-change symbol stop-displayed. Namely, the changed odds can be varied according to the number of the odds-change symbol stop-displayed. Accordingly, it is possible to significantly increase the attention of the player on the number of the odds-change symbol stop-displayed. 
     Further, there may be occurred a case where the odds are changed to relatively advantageous odds or disadvantageous odds for the player, according to the number of the odds-change symbol stop-displayed. In the case that odds are changed to the relatively advantageous odds for the player, the player may be delighted, and on the other hand, in the case that odds are changed to the disadvantageous odds for the player, the player may be disappointed. As thus described, the change of odds can take the player through emotional ups and downs. Consequently, the player can be absorbed in the game. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, the slot machine comprises: a symbol display capable of variably displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds; and a controller. The controller is programmed to execute processing of (A) stop-displaying the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, following a BET of a game medium in amount corresponding to natural number multiple of a predetermined minimum BET unit; (B) determining an amount of payout based on normal odds indicating a relation between the stop-displayed normal symbol and the amount of payout and on the normal symbol stop-displayed in the processing (A), (C) stop-displaying, when the odds-change symbol is stop-displayed in the processing (A), the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, following the BET of the game medium in amount corresponding to the natural number multiple of a special BET unit bigger than the minimum BET unit, in a game subsequent to the game in which the odds-change symbol has been stop-displayed, (D) determining the amount of payout based on special odds different from the normal odds and on the normal symbol stop-displayed in the processing (C), and (E) paying out the game medium in the amount of payout determined in any one of the processing (B) and the processing (D). 
     According to the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined based on the special odds different from the normal odds, in the game subsequent to the game in which the odds-change symbol has been stop-displayed. Namely, the odds are changed. 
     As thus described, according to the slot machine, the odds are changed as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the change of the odds and thus fully enjoy the game. 
     Further, since the odds are changed in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, according to the slot machine, in the game in which the amount of payout is determined based on the normal odds (in the present description, referred to as normal game), the variable-display and the stop-display of the plurality of symbols are conducted after the game medium in the amount corresponding to the natural number multiple of the minimum BET unit is BET. On the other hand, in the game in which the amount of payout is determined based on the special odds (in the present description, referred to as special game), the variable-display and the stop-display of the plurality of symbols are conducted after the game medium in the amount corresponding to the natural number multiple of the special BET unit is BET. The special BET unit is bigger than the minimum BET unit. 
     Namely, according to the slot machine, the BET unit (the minimum unit to BET) in the special game is bigger than the BET unit in the normal game. Accordingly, it is possible to have the player place a BET of the game medium in a big number, which leads to a profit increase of a recreation hall. Further, not only the odds, but also the BET unit is changed as triggered by the stop-display of the odds-change symbol. Accordingly, it is possible to provide an unpredictable element to the player and increase an interesting aspect of the game. Furthermore, since the player can acquire a big payout by placing a BET of the game medium in a big number under a condition of the increased BET unit, it is possible to increase the player&#39;s expectation for the payout. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, the slot machine further comprising an input device with which a player can input an order relating to the game. Furthermore, the controller is programmed to execute processing of: (F) accepting from the input device an input of an disapproval order of a change indicating disapproval for the change in odds, and the processing (C) is processing of stop-displaying the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, following the BET of the game medium in amount corresponding to the natural number multiple of the special BET unit, on condition that the input of the disapproval order of the change has not been made in the processing (F). 
     According to the slot machine, the BET unit is changed to the special BET unit on condition that the disapproval order of the change has not been inputted. Namely, the player can prevent the increase in the BET unit by inputting the disapproval order of the change. Accordingly, the player reluctant to BET the game media in a large number can continue the game based on the minimum BET unit. Consequently, it is possible to provide a sense of satisfaction to the player. 
     Further, according to the slot machine, in the case that the disapproval order of change is inputted, the odds are not changed. Therefore, in the case that the player wishes to change the odds while not wishing to change the BET unit, the player has choices, namely, changing the odds or not changing the BET unit. Concurrently, it is possible to have the player go through a process of trial and error in selecting either choice, and through such a process, the player can be absorbed in the game. 
     The present invention provides a slot machine having the following configuration. 
     That is, the aforementioned slot machine comprises: a symbol display capable of stop-displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds after variably displaying the plurality of symbols; a memory capable of storing normal odds data indicating a relation between the normal symbol stop-displayed to the symbol display and an amount of payout and being to be referred to when the odds-change symbol has not been stop-displayed, and special odds data to be referred to when the odds-change symbol has been stop-displayed; and a controller. The controller is programmed to execute processing of (A) stop-displaying the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, (B) determining the amount of payout based on the normal symbol stop-displayed in the processing (A) and on the normal odds data stored in the memory when the odds-change symbol has not been stop-displayed in the processing (A), (C) determining the amount of payout based on the normal symbol stop-displayed in the processing (A) and on the special odds data stored in the memory, when the odds-change symbol has been stop-displayed in the processing (A), (D) paying out a game medium in the amount of payout determined in any one of the processing (B) and the processing (C). 
     According to the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined with reference to the special odds data different from the normal odds data to be referred to when the odds-change symbol is not stop-displayed. 
     As thus described, according to the slot machine, the payout is conducted based the unusual odds (odds indicated by the special odds data) as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the variety of the odds and thus fully enjoy the game. 
     Further, since the payout is conducted based on the unusual odds in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, the processing (C) is processing of determining the amount of payout based on the normal symbol stop-displayed in the processing (A) and on the special odds data stored in the memory, when a number of the odds-change symbol stop-displayed in the processing (A) satisfies a predetermined condition. 
     According to the slot machine, the payout is conducted based on the unusual odds in the case that the number of the odds-change symbol stop-displayed satisfies the predetermined condition. Accordingly, whether or not the number of odds-change symbol satisfies the predetermined condition, namely, how many odds-change symbols are stop-displayed is of great concern for the player. Therefore, it is possible to have the player find great pleasure in counting the number of the odds-change symbol while playing the game. Consequently, it is possible to have the player fully enjoy the game. 
     Further, the slot machine of the present invention preferably has the following configuration. 
     That is, a plurality of the special odds data are stored in the memory, and each special odds data is associated with the number of the odds-change symbol stop-displayed to the symbol display. The processing (C) is processing of determining the amount of payout based on the normal symbol stop-displayed in the processing (A) and on the special odds data associated with the number of the odds-change symbol stop-displayed in the processing (A). 
     According to the slot machine, in the case that the number of the odds-change symbol stop-displayed satisfies the predetermined condition, the special odds data corresponding to the number of the odds-change symbol stop-displayed is to be referred when the amount of payout is determined. Namely, the payout based on the different odds can be conducted according to the number of the odds-change symbol stop-displayed. Accordingly, it is possible to significantly increase the attention of the player on the number of the odds-change symbol stop-displayed. 
     Further, there may be occurred a case where the payout is conducted based on the relatively advantageous odds or the disadvantageous odds for the player, according to the number of the odds-change symbol stop-displayed. In the case that the payout is conducted based on the relatively advantageous odds for the player, the player may be delighted, and on the other hand, in the case that the payout is conducted based on the disadvantageous odds for the player, the player may be disappointed. As thus described, the variety of odds based on the payout can take the player through emotional ups and downs. Consequently, the player can be absorbed in the game. 
     Further, the present invention provides a control method of a slot machine. 
     That is, the control method of a slot machine comprises steps of: (A) stop-displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds, after variably displaying the plurality of symbols to the symbol display; (B) determining an amount of payout based on normal odds indicating a relation between the stop-displayed normal symbol and the amount of payout and on the normal symbol stop-displayed in the step (A); (C) determining, when the odds-change symbol has been stop-displayed in the step (A), the amount of payout based on special odds different from the normal odds and on the normal symbol stop-displayed in the step (A), instead of executing the step (B), in a game subsequent to the game in which the odds-change symbol has been stop-displayed, and (D) paying out a game medium in the amount of payout determined in any one of the step (B) and the step (C). 
     According to the control method of the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined based on the special odds different from the normal odds, in the game subsequent to the game in which the odds-change symbol has been stop-displayed. Namely, the odds are changed. 
     As thus described, according to the control method of the slot machine, the odds are changed as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the change of the odds and thus fully enjoy the game. 
     Further, since the odds are changed in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, the present invention provides a control method of a slot machine. That is the control method of a slot machine comprises steps of: (A) stop-displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds, after variably displaying the plurality of symbols to the symbol display, following a BET of a game medium in amount corresponding to natural number multiple of a predetermined minimum BET unit; (B) determining an amount of payout based on normal odds indicating a relation between the stop-displayed normal symbol and the amount of payout and on the normal symbol stop-displayed in the step (A), (C) stop-displaying, when the odds-change symbol is stop-displayed in the step (A), the plurality of symbols after variably displaying the plurality of symbols, to the symbol display, following the BET of the game medium in amount corresponding to the natural number multiple of a special BET unit bigger than the minimum BET unit, in a game subsequent to the game in which the odds-change symbol has been stop-displayed, (D) determining the amount of payout based on special odds different from the normal odds and on the normal symbol stop-displayed in the step (C), and (E) paying out the game medium in the amount of payout determined in any one of the step (B) and the step (D). 
     According to the control method of the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined based on the special odds different from the normal odds, in the game subsequent to the game in which the odds-change symbol has been stop-displayed. Namely, the odds are changed. 
     As thus described, according to the control method of the slot machine, the odds are changed as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the change of the odds and thus fully enjoy the game. 
     Further, since the odds are changed in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, according to the control method of the slot machine, in the game in which the amount of payout is determined based on the normal odds, the variable-display and the stop-display of the plurality of symbols are conducted after the game medium in the amount corresponding to the natural number multiple of the minimum BET unit is BET. On the other hand, in the game in which the amount of payout is determined based on the special odds, the variable-display and the stop-display of the plurality of symbols are conducted after the game medium in the amount corresponding to the natural number multiple of the special BET unit is BET. The special BET unit is bigger than the minimum BET unit. 
     Namely, according to the control method of the slot machine, the BET unit (the minimum unit to BET) in the special game is bigger than the BET unit in the normal game. Accordingly, it is possible to have the player place a BET of the game medium in a big number, which leads to a profit increase of a recreation hall. Further, not only the odds, but also the BET unit is changed as triggered by the stop-display of the odds-change symbol. Accordingly, it is possible to provide an unpredictable element to the player and increase an interesting aspect of the game. Furthermore, since the player can-acquire a big payout by placing a BET of the game medium in a big number under a condition of the increased BET unit, it is possible to increase the player&#39;s expectation for the payout. 
     Further, the present invention provides a control method of a slot machine. That is the control method of a slot machine comprises steps of: (A) stop-displaying a plurality of symbols including a normal symbol and an odds-change symbol as a trigger for changing odds after variably displaying the plurality of symbols, to the symbol display, (B) determining an amount of payout based on the normal symbol stop-displayed in the step (A) and on normal odds data indicating a relation between the stop-displayed normal symbol and the amount of payout, when the odds-change symbol has not been stop-displayed in the step (A), (C) determining the amount of payout based on the normal symbol stop-displayed in the step (A) and on the special odds data different from the normal odds data, when the odds-change symbol has been stop-displayed in the step (A), and (D) paying out a game medium in the amount of payout determined in any one of the step (B) and the step (C). 
     According to the control method of the slot machine, the odds-change symbols can be stop-displayed to the symbol display. In the case that the odds-change symbol is stop-displayed, the amount of payout is determined with reference to the special odds data different from the normal odds data to be referred to when the odds-change symbol is not stop-displayed. 
     As thus described, according to the control method of the slot machine, the payout is conducted based the unusual odds (odds indicated by the special odds data) as triggered by the stop-display of the odds-change symbol. Accordingly, it becomes possible to have a player enjoy the variety of the odds and thus fully enjoy the game. 
     Further, since the payout is conducted based on the unusual odds in the case that the odds-change symbol has been stop-displayed, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the stop-display of the odds-change symbol, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
    
    
     
       BRIEF DESCRIPTIONS OF DRAWINGS 
         FIG. 1A  is a view illustrating an exemplary symbol matrix. 
         FIG. 1B  is a view illustrating an exemplary image to be displayed to a lower image display panel. 
         FIG. 2  is a view illustrating a relation among a number of rearranged odds-change symbol and a special game and special odds. 
         FIG. 3A  is a view illustrating normal odds. 
         FIG. 3B  is a view illustrating special odds A. 
         FIG. 3C  is a view illustrating special odds B. 
         FIG. 3D  is a view illustrating special odds C. 
         FIG. 4  is a perspective view illustrating the external appearance of a slot machine. 
         FIG. 5  is a block diagram illustrating an internal configuration of the slot machine illustrated in  FIG. 4 . 
         FIG. 6  is a flowchart illustrating main processing executed in the slot machine  10  according to a first embodiment. 
         FIG. 7  is a flowchart illustrating a subroutine of normal game execution processing. 
         FIG. 8  is a flowchart illustrating a subroutine of special game A execution processing. 
         FIG. 9  is a flowchart illustrating a subroutine of special game B execution processing. 
         FIG. 10  is a flowchart illustrating a subroutine of special game C execution processing. 
         FIG. 11  is a flowchart illustrating a procedure of activation processing. 
         FIG. 12  is a view illustrating peripheral device initialization processing. 
         FIG. 13  is a flowchart illustrating a subroutine of activation processing executed by a central controller. 
         FIG. 14  is a flowchart illustrating a subroutine of slot machine game execution processing according to a second embodiment. 
         FIG. 15  is a flowchart illustrating a subroutine of payout processing according to a second embodiment. 
         FIG. 16  is a perspective view illustrating an external appearance of a slot machine according to another embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     First Embodiment 
     A general description of a first embodiment will be given by using  FIG. 1A ,  FIG. 1B ,  FIG. 2 ,  FIG. 3A  to  FIG. 3D . 
       FIG. 1A  is a view illustrating an exemplary symbol matrix. 
       FIG. 1B  is a view illustrating an exemplary image to be displayed to a lower image display panel. 
       FIG. 2  is a view illustrating a relation among a number of rearranged odds-change symbol and a special game and special odds. 
       FIG. 3A  is a view illustrating normal odds. 
       FIG. 3B  is a view illustrating special odds A. 
       FIG. 3C  is a view illustrating special odds B. 
       FIG. 3D  is a view illustrating special odds C. 
     In a slot machine  10  (see  FIG. 4 ) according to the first embodiment, an odds-change symbol  100  (see  FIG. 1A ) may be rearranged in a symbol matrix SM. The symbol matrix SM is displayed to a lower image display panel  16  provided in the slot machine  10 . The lower image display panel  16  (see  FIG. 4 ) corresponds to the symbol display of the present invention. 
     In the case that three, four, or five odds-change symbols  100  are rearranged, odds-change text images  101 A to  101 E as illustrated in  FIG. 1B  may be displayed to the lower image display panel  16 . 
     An example in  FIG. 1A  shows a state that three odds-change symbols  100  are rearranged. Triggered by this, the odds-change text image  101 A for notifying a player of “appearance of three odds-change symbols 100” is displayed in  FIG. 1B . 
     The odds-change text image  101 B is for notifying the player of “an increase in odds from the next game”. The odds are determined for each type and each number of the stop-displayed normal symbol, and indicate the number of coin-outs in the case that a single coin is BET (see  FIGS. 3A to 3D ). 
     The odds may be changed to different odds in the case that three odds-change symbols  100  are stop-displayed, in the case that four odds-change symbols  100  are stop-displayed, and in the case that five odds-change symbols  100  are stop-displayed (see  FIG. 2 ). 
     In the case that three odds-change symbols  100  are rearranged, a special odds A may be adopted from the game subsequent to the game in which three odds-change symbols  100  are rearranged. In the case that four odds-change symbols  100  are rearranged, a special odds B may be adopted from the game subsequent to the game in which four odds-change symbols  100  are rearranged. In the case that five odds-change symbols  100  are rearranged, a special odds C may be adopted from the game subsequent to the game in which five odds-change symbols are rearranged. 
     The special odds A, the special odds B, and the special odds C constitute the special odds of the present invention. Further, “(the number of the rearranged odds-change symbol  100 ) being 3, 4, or 5” corresponds to the predetermined condition of the present invention. 
     As illustrated in  FIG. 2 , a slot machine game executed based on the special odds A is referred to as a special game A in the present description. A slot machine game executed based on the special odds B is referred to as a special game B in the present description. A slot machine game executed based on the special odds C is referred to as a special game C in the present description. 
     The slot machine game including the special game A, the special game B, and the special game C is referred to as a special game in the present description. The slot machine game other than the special game is referred to as a normal game in the present description. Odds in the normal game correspond to the normal odds of the present invention. 
     In examples illustrated in  FIG. 3A  to  FIG. 3D , the special odds A, the special odds B, and the special odds C respectively have bigger values than the normal odds. 
     In the normal game, for example, in the case that three “SUN” are rearranged after two coins have been BET, 20 (=2×10) coins are paid out (see  FIG. 3A ). 
     On the other hand, for example, in the case that three odds-change symbols  100  are rearranged as illustrated in  FIG. 1A , the game subsequent to the game in which three odds-change symbols  100  are rearranged is the special game A executed based on the special odds A. In the special odds A, for example, three “SUN” are rearranged after two coins have been BET, 30 (=2×15) coins are paid out (see  FIG. 3B ). 
     Here, in the first embodiment, there are eight types of the normal symbols to be rearranged in the symbol matrix SM, namely, “RIBBON”, “STAR”, “MOON”, “SUN”, “JEWEL”, “CROWN”, and “SMILE”. Further, all the normal symbols comprise so-called scatter symbols. 
     As above described, in the case that three, four, or five odds-change symbols  100  are rearranged, the odds may be changed, however, in the case that the player inputs a predetermined order, the odds are not changed. 
     The odds-change text image  101 C is for notifying the player of “the BET unit increasing with increase in odds”. The BET unit is a minimum unit to BET. 
     In the first embodiment, the BET unit in the normal game (the minimum BET unit in the present invention) is a single coin. The BET unit in the special game A (special BET unit A)is two coins. The BET unit in the special game B (special BET unit B) is four coins. The BET unit (special BET unit C) in the special game C is eight coins. The special BET unit A, the special BET unit B, and the special BET unit C are included in the special BET unit of the present invention. 
     As thus described, in the slot machine  10  according to the first embodiment, the minimum BET unit in the special game is set to be larger than the minimum BET unit in the normal game. 
     The odds-change text image  101 D is for notifying the player of “being able to increase in BET unit, if you want”. The player can input the order indicating not to increase the BET unit by touching a place on a touch panel  69  (input device of the present invention) corresponding to a text of “HERE” shown by the odds-change text image  101 D. 
     However, in the case that the order indicating not to increase the BET unit is inputted, the odds are not increased. Namely, even three, four, or five odds-change symbols are rearranged, the odds are not changed in the case that the order indicating not to increase the BET unit has been inputted. The order indicating not to increase the BET unit corresponds to the disapproval order of change of the present invention. 
     There has been described the outline of the first embodiment. 
     Hereinafter, the first embodiment will be described in more detail. 
       FIG. 4  is a perspective view illustrating the external appearance of the slot machine. 
     In the slot machine  10 , a coin, a bill, or electronic valuable information corresponding thereto is used as a game medium. However, in the present invention, a game medium is not particularly limited. Examples of the game medium may include a medal, a token, electronic money, or a ticket. It should be noted that the ticket is not particularly limited, and examples thereof include a ticket with a bar code, which will be described later. 
     Here, the slot machine  10  is a stand-alone type slot machine that is not connected to a network, but the present invention can also be applied to a slot machine connected to a network. 
     The slot machine  10  includes: a cabinet  11 ; a top box  12  placed on the upper side of the cabinet  11 ; and a main door  13  provided at the front face of the cabinet  11 . The lower image display panel  16  is provided in front of the main door  13 . The lower image display panel  16  includes a liquid crystal display panel and the symbol matrix SM (see  FIGS. 1A ) is displayed thereto. In the lower image display panel  16 , there are provided a number-of-credits display section  31  and a number-of-payouts display section  32 (not shown). 
     The number-of-credits display section  31  displays an image indicating the number of credited coins. The number-of-payouts display section  32  displays an image indicating the number of coins to be paid out as the payout. 
     Further, a touch panel  69 , which is not shown in the figure, is provided on the front face of the lower image display panel  16 , and the player can input various kinds of commands by operating the touch panel  69 . 
     Below the lower image display panel  16 , there are provided a control panel  20  comprised of a plurality of buttons  23  to  27  with each of which a command according to the game progress is inputted by the player, a coin receiving slot  21  through which a coin is accepted into the cabinet  11 , and a bill validator  22 . 
     The control panel  20  is provided with a start button  23 , a change button  24 , a CASHOUT button  25 , a 1-BET button  26 , and a maximum BET button  27 . The start button  23  is used for inputting a command to start a game. The change button  24  is used for making a request of staff at a recreation facility for exchange. The CASHOUT button  25  is used for inputting a command to pay out credited coins to a coin tray  18 . 
     The 1-BET button  26  is used for inputting a command to BET one coin on a game out of credited coins. The maximum BET button  27  is used for inputting a command to BET the maximum number (10 in the normal game, 20 in the special game A, 40 in the special game B, 80 in the special game C) of coins that can be bet on a single game out of credited coins. 
     The bill validator  22  not only discriminates a regular bill from a false bill, but also accepts the regular bill into the cabinet  11 . It should be noted that the bill validator  22  may be configured so as to be capable of reading a later-described ticket  39  with a barcode. At the lower front face of the main door  13 , namely below the control panel  20 , there is provided a belly glass  34  on which a character or the like of the slot machine  10  is drawn. 
     At the front face of the top box  12 , an upper image display panel  33  is provided. The upper image display panel  33  is provided with a liquid crystal panel to display, for example, an image representing an introduction of the contents of a game or a description of a rule of the game. 
     Further, the top box  12  is provided with a speaker  29 . Below the upper image display panel  33 , there are provided a ticket printer  35 , a card reader  36 , a data display  37 , and a keypad  38 . The ticket printer  35  prints on a ticket a barcode as coded data of the number of credits, date and time, an identification number of the slot machine  10 , and the like, and outputs the ticket as a ticket  39  with a barcode. The player can make another slot machine read the ticket  39  with a barcode to play a game thereon, or can exchange the ticket  39  with a barcode with bills or the like at a predetermined place in the recreation facility (for example, a cashier in a casino). 
     The card reader  36  reads data from a smart card and writes data into the smart card. The smart card is a card owned by the player, and for example, data for identifying a player and data on a history of games played by the player are stored therein. Data corresponding to a coin, a bill, or a credit may be stored in the smart card. Further, in place of the smart card, a magnetic stripe card may be adopted. The data display  37  is comprised of a fluorescent display or the like, and displays, for example, data read by the card reader  36  or data inputted by the player through the keypad  38 . The keypad  38  is used for inputting a command and data concerning the issue of a ticket and the like. 
       FIG. 5  is a block diagram showing an internal configuration of the slot machine shown in  FIG. 4 . 
     A gaming board  50  includes a CPU (Central Processing Unit)  51 , a ROM  55 , and a boot ROM  52  which are interconnected to one another via an internal bus, a card slot  53 S corresponding to a memory card  53 , and an IC socket  54 S corresponding to a GAL (Generic Array Logic)  54 . 
     The memory card  53  is formed from a nonvolatile memory such as CompactFlash (registered trademark) and stores game programs and game system programs. The game programs include a symbol selection program. The aforementioned symbol selection program is a program for determining the symbols (normal symbol and odds-change symbol) to be rearranged in the symbol matrix SM. The aforementioned symbol selection program includes symbol weighing data in association with a plurality of types of payout ratios (for example, 80%, 84%, 88%). The symbol weighing data is data indicating the correspondence between the respective symbols, and one or more random numbers which fall in a predetermined numerical range (0 to 255). The payout ratios are determined based on payout-ratio setting data outputted from the GAL  54  and, based on the symbol weighing data associated with the payout ratios, the symbols to be rearranged in the symbol matrix are determined. 
     Further, the game programs include table data (see  FIG. 2 ) indicative of the corresponding relation between the type of the game (normal game, special game A, special game B, or special game C) and the odds (normal odds, special odds A, special odds B, or special odds C). Further, the game programs include normal odds data (see  FIG. 3A ) indicative of the normal odds, special odds A data (see  FIG. 3B ) indicative of the special odds A, special odds B data (see  FIG. 3C ) indicative of the special odds B, and special odds C data (see  FIG. 3D ) indicative of the special odds C. 
     Further, the card slot  53 S is configured so as to allow the memory card  53  to be inserted there into or ejected therefrom, and is connected to a mother board  40  via an IDE bus. Thus, the memory card  53  can be ejected from the card slot  53 S, and then another game program is written onto the memory card  53 , and the memory card  53  can be inserted into the card slot  53 S, to change the type and contents of a game to be played on the slot machine  10 . The game program includes a program associated with the progress of a game. The game program also includes image data and sound data to be outputted during the game. The image data includes image data indicating a symbol matrix. 
     The GAL  54  is a type of PLD having a fixed OR array structure. The GAL  54  includes plural input ports and plural output ports and, when predetermined data is inputted to an input port, the GAL  54  outputs data corresponding to the aforementioned data from an output port. The data outputted from this output port is the aforementioned payout-ratio setting data. 
     Further, the IC socket  54 S is configured to allow the GAL  54  to be attached thereto and detached therefrom and is connected to the mother board  40  through a PCI bus. Accordingly, the GAL  54  can be replaced with another GAL  54  to change the payout-ratio setting data. 
     A CPU  51 , a ROM  55  and a boot ROM  52  interconnected to one another via an internal bus are connected to the mother board  40  by PCI bus. The PCI bus supplies power to the gaming board  50  from the mother board  40 , as well as transmitting a signal between the mother board  40  and the gaming board  50 . The ROM  55  stores country identification information and an authentication program. The boot Rom  52  stores an auxiliary authentication program and a program (boot code) to be used by the CPU  51  for activating the auxiliary authentication program, and the like. 
     The authentication program is a program (falsification check program) for authenticating a game program and a game system program. The authentication program is written along a procedure (authentication procedure) for checking and proving that a game program and a game system program to be subject to authentication loading processing have not been falsified, namely authenticating the game program and the game system program. The auxiliary authentication program is a program for authenticating the above-mentioned authentication program. The auxiliary authentication program is written along a procedure (authentication procedure) for proving that an authentication program to be subject to the authentication processing has not been falsified, namely, authenticating the authentication program. 
     The mother board  40  is constructed with a general-purpose mother board commercially available (a printed circuit board on which basic parts of a personal computer are mounted) and includes a main CPU  41 , ROM (Read Only Memory)  42  and RAM (Random Access Memory)  43 . The mother board  40  is the controller of the present invention. 
     ROM  42  is constituted of a memory device such as a flash memory and stores thereon a program such as BIOS (Basic Input/Output System) executed by the main CPU  41  and permanent data. When BIOS is executed by the main CPU  41 , not only is initialization processing for predetermined peripheral devices conducted, but a capture processing for the game program and game system program stored on the memory card  53  is also started via the gaming board  50 . In the present invention, contents of ROM  42  may be rewritable or not rewritable. 
     RAM  43  stores data and a program used at the time of operation of the main CPU  41 , and various flags. RAM  43  can also store the authentication program read through the gaming board  50 , the game program, and the game system program. RAM  43  further stores data on the number of credits, the number of coins-in or coins-out for one game, and the like. 
     Further, in the RAM  43 , a number-of-special-game-A storage area, a number-of-special-game-B storage area, and the number-of-special-game-C storage area are provided. The number-of-special-game-A storage area stores data indicating the remaining number of the special game A. The number-of-special-game-B storage area stores data indicating the remaining number of the special game B. The number-of-special-game-C storage area stores data indicating the remaining number of the special game C. 
     To the mother board  40 , a body PCB (Printed Circuit Board)  60  and a door PCB  80 , which will be described later, are connected through respective USBs. Further, the mother board  40  is connected with a power supply unit  45 . When the power is supplied from the power unit  45  to the mother board  40 , the main CPU  41  of the mother board  40  is activated and the power is supplied to the gaming board  50  through the PCI bus so that the CPU  51  is activated. 
     The body PCB  60  and the door PCB  80  are connected with equipment and devices that generate input signals to be inputted to the main CPU  41 , and equipment and devices operations of which are controlled by control signals outputted from the main CPU  41 . The main CPU  41  executes a game program stored in the RAM  43  based on an input signal inputted to the main CPU  41 , thereby executes the predetermined arithmetic processing and stores a result thereof in the RAM  43 , or transmits a control signal to each of the equipment and devices as processing for controlling each of the equipment and devices. 
     To the body PCB  60 , there are connected a lamp  30 , a hopper  66 , a coin detecting portion  67 , a graphic board  68 , a speaker  29 , a touch panel  69 , a bill validator  22 , a ticket printer  35 , a card reader  36 , a key switch  38 S, and a data display  37 . The lamp  30  lights up in a predetermined pattern based on a control signal outputted from the main CPU  41 . 
     The hopper  66  is installed inside the cabinet  11  and pays out a predetermined number of coins from the coin payout exit  19  to the coin tray  18 , based on a control signal outputted from the main CPU  41 . The coin detecting portion  67  is provided inside the coin payout exit  19 , and outputs an input signal to the main CPU  41  when detecting a payout of a predetermined number of coins from the coin payout exit  19 . 
     The graphic board  68  controls, based on a control signal outputted from the main CPU  41 , an image display to the upper image display panel  33  and the lower image display panel  16 . The number of credits stored in RAM  43  is displayed to the number-of-credits display section  31  (not shown) of the lower image display panel  16 . The number of coins-out is displayed to the number-of-payouts display section  32  (not shown) of the lower image display panel  16 . The graphic board  68  is equipped with VDP (Video Display Processor) which generates image data based on a control signal outputted from the main CPU  41  and a video RAM which temporarily stores image data generated by VDP, and of the like equipments. It should be noted that image data used in generating image data with VDP is contained in a game program read from the memory card  53  and stored in RAM  43 . 
     The bill validator  22  not only discriminates a regular bill from a false bill, but also accepts the regular bill into the cabinet  11 . When accepting a regular bill, the bill validator  22  outputs an input signal to the main CPU  41 , based on the face amount of the bill. The main CPU  41  stores, in the RAM  43 , the number of credits according to the face amount of the bill transmitted with the input signal. 
     The ticket printer  35  prints on a ticket, based on a control signal outputted from the main CPU  41 , a barcode formed by encoding data such as the number of credits, date and time, an identification number of the slot machine  10 , and of the like data stored in the RAM  43 , and outputs the ticket as a ticket  39  with a barcode. 
     The card reader  36  reads data from a smart card and transmits the data to the main CPU  41  or writes data into the smart card based on a control signal from the main CPU  41 . The key switch  38 S is provided on the keypad  38 , and outputs a predetermined input signal to the main CPU  41  when the keypad  38  is operated by the player. The data display  37  displays, based on a control signal outputted from the main CPU  41 , data read by the card reader  36  or data inputted by the player through the keypad  38 . 
     To the door PCB  80 , there are connected a control panel  20 , a reverter  21 S, a coin counter  21 C, and a cold cathode tube  81 . The control panel  20  is provided with a start switch  23 S corresponding to the start button  23 , a change switch  24 S corresponding to the change button  24 , a CASHOUT switch  25 S corresponding to the CASHOUT button  25 , a 1-BET switch  26 S corresponding to the 1-BET button  26 , and a maximum BET switch  27 S corresponding to the maximum BET button  27 . Each of the switches  23 S to  27 S outputs an input signal to the main CPU  41  when each of the buttons  23  to  27  corresponding thereto is operated by the player. 
     The coin counter  21 C is provided inside the coin receiving slot  21  and discriminates a regular coin from a false coin inserted into the coin receiving slot  21  by the player. Coins other than regular coins are discharged from the coin payout exit  19 . When the coin counter  21 C detects a regular coin, the coin counter  21 C outputs an input signal to the main CPU  41 . 
     The reverter  21 S operates based on a control signal outputted from the main CPU  41 , and distributes a coin identified by the coin counter  21 C as a regular coin into a cash box (not shown) or the hopper  66 , which are disposed in the slot machine  10 . Specifically, when the hopper  66  is filled with coins, a regular coin is distributed into the cash box by the reverter  21 S. On the other hand, when the hopper  66  is not filled with coins, the regular coin is distributed into the hopper  66 . The cold cathode tube  81  functions as a backlight installed on the rear face side of the lower image display panel  16  and the upper image display panel  33 , and lights up based on a control signal to be outputted from the main CPU  41 . 
     Next, processing executed in the slot machine  10  will be described. 
       FIG. 6  is a flowchart illustrating main processing executed in the slot machine  10  according to a first embodiment. 
     First, in the slot machine  10 , activation processing is executed (step S 101 ). The activation processing will be specifically described later by using  FIG. 10  to  FIG. 12 . 
     After the activation processing, the main CPU  41  executes processing of addition of the number of credits stored in the RAM  43  as an interrupt processing, on receiving a detection signal outputted from the coin counter  21 C when the coin inserted into the coin receiving slot  21  is detected by the coin counter  21 . 
     After the processing of step S 101 , the main CPU  41  determines whether or not s special game C flag is set (step S 102 ). The special game C flag is a flag to be set as triggered by the rearrangement of five odds-change symbols  100 , and is a flag indicating that it is currently the special game C period (see step S 30  in  FIG. 7 ). 
     When determining that the special game C flag is set, the main CPU  41  executes special game C execution processing (step S 500 ). The special game C execution processing will be specifically described later by using  FIG. 9 . After executing the processing of step S 500 , the main CPU  41  returns the processing to step S 102 . 
     When determining that the special game C flag is not set, the main CPU  41  determines whether or not a special game B flag is set (step S 103 ). The special game B flag is a flag to be set as triggered by the rearrangement of four odds-change symbols  100 , and is a flag indicating that it is currently the special game B period (see step S 25  in  FIG. 7 ). 
     When determining that the special game B flag is set, the main CPU  41  executes special game B execution processing (step S 400 ). The special game B execution processing will be specifically described later by using  FIG. 8 . After executing the processing of step S 400 , the main CPU  41  returns the processing to step S 102 . 
     When determining that the special game B flag is not set, the main CPU  41  determines whether or not a special game A flag is set (step S 104 ). The special game A flag is a flag to be set as triggered by the rearrangement of three odds-change symbols, and is a flag indicating that it is currently the special game A period (see step S 20  in  FIG. 7 ). 
     When determining that the special game A flag is set, the main CPU  41  executes special game A execution processing (step S 300 ). The special game A execution processing will be specifically described later by using  FIG. 7 . After executing the processing of step S 300 , the main CPU  41  returns the processing to step S 102 . 
     When determining that the special game A flag is not set, the main CPU  41  executes normal game execution processing (step S 200 ). The normal game execution processing will be specifically described later by using  FIG. 6 . After executing the processing of step S 200 , the main CPU  41  returns the processing to step S 102 . 
     Hereinafter, slot machine game execution processing (normal game execution processing, special game A execution processing, special game B execution processing, and special game C execution processing) executed in the slot machine  10  will be described. 
     The main CPU  41  reads a game program and executes the game program to progress a slot machine game. 
       FIG. 7  is a flowchart illustrating a subroutine of normal game execution processing. 
     First, the main CPU  41  determines whether or not a coin has been BET (step S 11 ). In the processing, the main CPU  41  determines whether or not to have received an input signal outputted from the 1-BET switch  26 S when the 1-BET button  26  is operated or an input signal outputted from the maximum BET switch  27 S when the maximum BET button  27  is operated. When determining that a coin has not been BET, the main CPU  41  returns the processing to step S 11 . 
     On the other hand, when determining that a coin has been BET in step S 11 , the main CPU  41  executes processing for making a subtraction from the number of credits stored in the RAM  43 , according to the number of BET coins (step S 12 ). It should be noted that, when the number of BET coins is larger than the number of credits stored in the RAM  43 , the main CPU  41  does not execute the processing for making a subtraction from the number of credits stored in the RAM  43 , and returns the processing to step S 11 . When the number of BET coins exceeds an upper limit of the number of coins that can be BET on a single game (10 in the normal game), the main CPU  41  does not execute the processing for making a subtraction from the number of credits stored in the RAM  43 , and the processing is proceeded to step S 13 . 
     Next, the main CPU  41  determines whether or not the start button  23  has been turned on (step S 13 ). In the processing, the main CPU  41  determines whether or not to have received an input signal outputted from the start switch  23 S when the start button  23  is pressed. 
     When determining that the start button  23  has not been turned ON, the main CPU  41  returns the processing to step S 11 . It should be noted that, when the start button  23  is not turned ON (for example, when a command to end the game is inputted without pressing the start button  23 ), the main CPU  41  cancels a result of the subtraction obtained in step S 12 . 
     On the other hand, when determining in step S 13  that the start button  23  has been turned ON, the main CPU  41  executes symbol rearrangement processing (step S 14 ). 
     In the processing, at first, the main CPU  41  starts scroll-display of the symbols (normal symbol and odds-change symbol) in the symbol matrix SM. Then, the main CPU  41  executes the above-mentioned symbol selection program, determines symbols to be rearranged, and rearranges the symbols in the symbol matrix SM. 
     Next, the main CPU  41  determines whether or not a prize is established (step S 17 ). Here, the establishment of the prize refers to the rearrangement of three or more normal symbols of at least one type, out of “RIBBON”, “HEART”, “STAR”, “MOON”, “SUN”, “JEWEL”, “CROWN”, and “SMILE”, in the symbol matrix SM (see  FIG. 3 ). In the processing, the main CPU  41  counts the number of normal symbol for each type, with regard to the rearranged symbols in step S 14 . Then, the main CPU  41  determines whether or not the counted number is equal to or more than three. 
     When determining that the prize has been established, the main CPU  41  executes processing according to payout of the coin (step S 16 ). In the processing, the main CPU  41  determines the amount of payout based on the number of rearranged symbols with reference to the normal odds data (see  FIG. 3A ) stored in the RAM  43 . 
     In the case of accumulating the coin, the main CPU  41  executes processing for adding an amount of credits corresponding to the determined amount of payout. On the other hand, in the case of paying out coins, the main CPU  41  transmits a control signal to the hopper  66  in order to pay out the coin in amount corresponding to the determined amount of payout. 
     When determining that the prize has not been established in step S 15  or after executing the processing of step S 16 , the main CPU  41  determines whether or not the number of the odds-change symbol rearranged in step S 14  is three (step S 17 ) 
     When determining that the number of the odds-change symbol is three, the main CPU  41  displays the odds-change text images  101 A to  101 E (see  FIG. 1B ) to the lower image display panel  16  (step S 18 ). At this time, triggered by the number of the odds-change symbol being three, the main CPU  41  displays the odds-change text image  101 A corresponding to “Three odds-change symbols appeared!!” to the lower image display panel  16 . 
     Then, the main CPU  41  accepts the input of the order indicating not to increase the BET unit (disapproval order of change). Thereafter, the main CPU  41  determines whether or not the disapproval order of the change has been inputted (step S 19 ) In the processing, the main CPU  41  determines whether or not to have received a signal outputted as triggered by the touch of the place on the touch panel  69  corresponding to the text of “HERE” shown by the odds-change text image  101 D, in a predetermined time. 
     When determining that the disapproval order of the change has not been inputted, the main CPU  41  sets the special game A flag (step S 20 ). 
     Then, the main CPU  41  sets the remaining number T A  of the special game A to T A =C A  (C A =10, in the first embodiment) in the number-of-special-game-A storage area in the RAM  43  (step S 21 ). 
     When determining that the disapproval order of the change has been inputted in step S 19  or after executing the processing of step S 21 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not three in step S 17 , the main CPU  41  determines whether or not the number of the odds-change symbol is four (step S 22 ). When determining that the number of the odds-change symbol is four, the main CPU  41  displays the odds-change text images  101 A to  101 E (see  FIG. 1B ) to the lower image display panel  16  (step S 23 ). At this time, triggered by the number of the odds-change symbol being four, the main CPU  41  displays the odds-change text image  101 A corresponding to “Four odds-change symbols appeared!!” to the lower image display panel  16 . 
     Then, the main CPU  41  accepts the input of the order indicating not to increase the BET unit (disapproval order of change). Thereafter, the main CPU  41  determines whether or not the disapproval order of change has been inputted (step S 19 ). In the processing, the main CPU  41  determines whether or not to have received a signal outputted as triggered by the touch of the place on the touch panel  69  corresponding to the text of “HERE” shown by the odds-change text image  101 D. 
     When determining that the disapproval order of change has not been inputted, the main CPU  41  sets the special game B flag (step S 25 ). 
     Then, the main CPU  41  sets the remaining number T B  of the special game B to T B =C B  (C B =15, in the first embodiment) in the number-of-special-game-B storage area in the RAM  43  (step S 26 ). 
     When determining that the disapproval order of change has been inputted in step S 24  or after executing the processing of step S 26 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not four instep S 22 , the main CPU  41  determines whether or not the number of the odds-change symbol is five (step S 27 ). When determining that the number of the odds-change symbol is five, the main CPU  41  displays the odds-change text images  101 A to  101 E (see  FIG. 1B ) to the lower image display panel  16  (step S 28 ). At this time, triggered by the number of the odds-change symbol being five, the main CPU  41  displays the odds-change text image  101 A corresponding to “Five odds-change symbols appeared!!” to the lower image display panel  16 . 
     Then, the main CPU  41  accepts the input of the order indicating not to increase the BET unit (disapproval order of change). Thereafter, the main CPU  41  determines whether or not the disapproval order of the change has been inputted (step S 29 ) In the processing, the main CPU  41  determines whether or not to have received a signal outputted as triggered by the touch of the place on the touch panel  69  corresponding to the text of “HERE” shown by the odds-change text image  101 D. 
     When determining that the disapproval order of the change has not been inputted, the main CPU  41  sets the special game C flag (step S 30 ). 
     Then, the main CPU  41  sets the remaining number T C  of the special game C to T C =C C  (C C =30, in the first embodiment) in the number-of-special-game-C storage area in the RAM  43  (step S 31 ). 
     When determining that the number of the odds-change symbol is not four in step S 27  or determining that the disapproval order of change has been inputted in step S 24  or after executing the processing of step S 31 , the main CPU  41  terminates the present subroutine. 
     The normal game execution processing (see step S 200  in  FIG. 6 ) has been described by using  FIG. 7 . 
     Next, the special game A execution processing (see step S 300  in  FIG. 6 ) will be described by using  FIG. 8 . 
       FIG. 8  is a flowchart illustrating a subroutine of special game A execution processing. 
     First, the main CPU  41  determines whether or not the coin in number equal to or more than the special BET unit A (two coins, in the first embodiment) have been BET (step S 111 ). In the processing, the main CPU  41  determines whether or not to have received an input signal outputted from the 1-BET switch  26 S when the 1-BET button  26  is operated or an input signal outputted from the maximum BET switch  27 S when the maximum-BET button  27  is operated. 
     When determining that the input signal outputted from the 1-BET switch  26 S has been received, the main CPU  41  determines that one coin has been BET. Further, when determining that the input signal outputted from the maximum BET switch  27 S has been received, the main CPU  41  determines that  20  coins have been BET. 
     When determining that two or more coins have not been BET, the main CPU  41  returns the processing to step S 111 . 
     As above described, in the first embodiment, there has been described the case that the main CPU  41  determines that one coin (minimum BET unit) has been BET when receiving the input signal outputted from the 1-BET switch  26 S in the special game period, in the same manner as in the normal game period. However, in the present invention, a main CPU may be set to determine that the game medium in amount corresponding to the special BET unit when receiving an input signal outputted from a 10BET switch in the special game period. 
     On the other hand, when determining that two or more coins have been BET in step S 111 , the main CPU  41  execute processing of subtraction of the number of credits stored in the RAM  43  according to the number M of the BET coin (step S 112 ). In the processing, the main CPU  41  subtracts the number of credits corresponding to the coins in number of 2N (=N×2) (N is the maximum integer satisfying 2N≦M). 
     Here, in the case that the number of BET coins is larger than the number of credits stored in the RAM  43 , the main CPU  41  returns the processing to step S 111  without executing the processing of subtraction of the number of credits stored in the RAM  43 . Further, in the case that the number of BET coins exceeds the upper limit (20, in the special game A) that can be BET in one game, the main CPU  41  proceeds the processing to step S 113  without executing the processing of subtraction of the number of credits stored in the RAM  43 . 
     Next, the main CPU  41  executes processing of step S 113  to step S 117 , and the processing is virtually the same processing as the processing of step S 13  to step S 17 . Here, only a part different from the processing of step S 13  to step S 17  will be described. 
     In step S 16  in  FIG. 7 , there has been described the case that the main CPU  41  refers to the normal odds data (see  FIG. 3A ) stored in the RAM  43  when determining the amount of payout. On the other hand, in step S 116  in  FIG. 8 , the main CPU  41  refers to the special odds A data (see  FIG. 3B ) stored in the RAM  43  when determining the amount of payout. 
     When determining the number of the odds-change symbol is three in step S 117 , the main CPU  41  sets the remaining number T A  of the special game A to T A =T A +C A −1 (C A =10, in the first embodiment) in the number-of-special-game-A storage area in the RAM  43  (step S 118 ). 
     After executing the processing of step S 118 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not three in step S 117 , the main CPU  41  executes processing of step S 119  to step S 121 . The processing is virtually the same processing as the processing of step S 22  to step S 24  in  FIG. 7  and the description thereof is omitted here. 
     When determining that the disapproval order of change has not been inputted in step S 121 , the main CPU  41  clears the special game A flag (step S 122 ). Then, the main CPU  41  sets the remaining number T A  of the special game A to T A =0 in the number-of-special-game-A storage area (step S 123 ). 
     Next, the main CPU  41  sets the special game B flag (step S 124 ). Then, the main CPU  41  sets the remaining number T B  of the special game B to T B =C B  (in the first embodiment, C B =15) in the number-of-special-game-B storage area in the RAM  43  (step S 125 ). 
     After executing the processing of step S 125 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not four in step S 119 , the main CPU  41  executes processing of step S 126  to step S 128 . The processing is virtually the same processing as the processing of step S 27  to step S 29  in  FIG. 7  and the description thereof is omitted here. 
     When determining that the disapproval order of the change has not been inputted in step S 121 , the main CPU  41  clears the special game A flag (step S 129 ). Then, the main CPU  41  sets the remaining number T A  of the special game A to T A =0 in the number-of-special-game-A storage area (step S 130 ). 
     Next, the main CPU  41  sets the special game C flag (step S 131 ). Then, the main CPU  41  sets the remaining number T C  of the special game C to T C =C C  (C C =30, in the first embodiment) in the number-of-special-game-C storage area in the RAM  43  (step S 132 ). 
     After executing the processing of step S 132 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not five in step S 126 , or when determining that the disapproval order of the change has been inputted in step S 121  or in step S 128 , the main CPU  41  sets the remaining number T A  of the special game A to T A =T A −1 in the number-of-special-game-A storage area in the RAM  43  (step S 133 ). 
     Next, the main CPU  41  determines whether or not the remaining number T A  of the special game A is T A =0 (step S 134 ). When determining that the remaining number T A  of the special game A is T A =0, the main CPU  41  clears the special game A flag (step S 135 ). 
     When determining that the remaining number T A  of the special game A is not T A =0, or after executing the processing of step S 135 , the main CPU  41  terminates the present subroutine. 
     There has been described the special game A execution processing (see step S 300  in  FIG. 6 ) by using  FIG. 8 . 
     As above described, the slot machine  10  according to the first embodiment is configured such that the remaining number of the special game A is increased in the case that three odds-change symbol are rearranged in the special game A (see step S 117  to step S 118 ). 
     Further, the slot machine  10  according to the first embodiment is configured such that, in the case that four odds-change symbols are rearranged in the special game A, the special game A is terminated and the special game B is executed from the next game, on condition that the disapproval order of the change has not been inputted (see step S 119  to step S 125 ). 
     Furthermore, the slot machine  10  according to the first embodiment is configured such that, in the case that five odds-change symbols are rearranged in the special game A, the special game A is terminated and the special game C is executed from the next game, on condition that the disapproval order of change has not been inputted (see step S 126  to step S 132 ). 
     Next, the special game B execution processing (see step S 400  in  FIG. 6 ) will be described by using  FIG. 9 . 
       FIG. 9  is a flowchart illustrating a subroutine of special game B execution processing. 
     First, the main CPU  41  executes the processing of step S 211  to step S 217 , and the processing is virtually the same processing as the processing of step S 111  to step S 117  in  FIG. 8 . Here, only a part different from the processing of step S 111  to step S 117  in  FIG. 8  will be described. 
     In step S 111  in  FIG. 8 , there has been described the case that the main CPU  41  determines whether or not the coins in number equal to or more than the special BET unit A (two, in the first embodiment) have been BET. On the other hand, in step S 211  in  FIG. 9 , the main CPU  41  determines whether or not the coins in number equal to or more than the special BET unit B (four coins, in the first embodiment) have been BET. 
     Further, in step S 111  in  FIG. 8 , there has been described the case that the main CPU  41  determines that  20  coins have been BET when determining to have received the input signal outputted from the maximum BET switch  27 S. On the other hand, in step S 211  in  FIG. 9 , the main CPU  41  determines that  40  coins have been BET when determining to have received the input signal outputted from the maximum BET switch  27 S. 
     In step S 112  in  FIG. 8 , there has been described the case that the main CPU  41  subtracts the number of credits corresponding to the coins in number of 2N (=N×2) (N is the maximum integer satisfying 2N≦M). On the other hand, in step S 212  in  FIG. 9 , the main CPU  41  subtracts the number of credits corresponding to the coins in number of 4N (=N×4) (N is the maximum integer satisfying 4N≦M). 
     In step S 116  in  FIG. 8 , there has been described the case that the main CPU  41  refers to the special odds A data (see FIG.  3 B) stored in the RAM  43  when determining the amount of payout. On the other hand, in step S 216  in  FIG. 9 , the main CPU  41  refers to the special odds B data (see  FIG. 3C ) stored in the RAM  43  when determining the amount of payout. 
     Next, when determining that the number of the odds-change symbol is three in step S 217 , the main CPU  41  clears the special odds B flag (step S 218 ) and sets the remaining number T B  of the special game B to T B =0 in the number-of-special-game-B storage area in the RAM  43  (step S 219 ) in the number-of-special-game-A storage area in the RAM  43 . 
     Next, the main CPU  41  sets the special game A flag (step S 220 ). Then, the main CPU  41  set the remaining number T A  of the special game A to T A =C A  (C A =10, in the first embodiment) (step S 221 ). 
     After executing the processing of step S 221 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not three in step S 217 , the main CPU  41  determines whether or not the number of the odds-change symbol is four (step S 222 ). 
     When determining that the number of the odds-change symbol is four, the main CPU  41  sets the remaining number T B  of the special game B to T B =T B +C B −1 (C B =15, in the first embodiment) in the number-of-special-game-B storage area in the RAM  43  (step S 223 ). 
     After executing the processing of step S 223 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not four in step S 222 , the main CPU  41  executes the processing of step S 224  to step S 226 , and the processing is virtually the same processing as the processing of step S 27  to step S 29  in  FIG. 7 . Therefore, the description thereof is omitted here. 
     When determining that the disapproval order of the change has not been inputted in step S 226 , the main CPU  41  clears the special game B flag (step S 227 ) and sets the remaining number T B  of the special game B to T B =0 in the number-of-special-game-B storage area in the RAM  43 (step S 228 ). 
     Next, the main CPU  41  sets the special game C flag (step S 229 ). Then, the main CPU  41  sets the remaining number T C  of the special game C to T C =C C  (C C =30, in the first embodiment) in the number-of-special-game-C storage area in the RAM  43  (step S 230 ). 
     After executing the processing of step S 230 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not five in step S 224 , or when determining that the disapproval order of the change has been inputted in step S 226 , the main CPU  41  sets the remaining number T B  of the special game B to T B =T B −1 in the number-of-special-game-B storage area in the RAM  43 (step S 231 ). 
     Next, the main CPU  41  determines whether or not the remaining number T B  of the special game B is T B =0 (step S 232 ). When determining that the remaining number T B  of the special game B is T B =0, the main CPU  41  clears the special game B flag (step S 233 ). 
     When determining that the remaining number T B  of the special game B is not T B =0 in step S 232 , or after executing the processing of step S 233 , the main CPU  41  terminates the present subroutine. 
     There has been described the special game B execution processing (see step S 400  in  FIG. 6 ) by using  FIG. 9 . 
     As above described, the slot machine  10  according to the first embodiment is configured such that, when three odds-change symbols are rearranged in the special game B, the special game B is terminated and the special game A is executed from the next game (see step S 217  to step S 221 ). In this case, the player cannot input the disapproval order of the change. 
     Further, the slot machine  10  according to the first embodiment is configured such that the remaining number of the special game B is increased when four odds-change symbols are rearranged in the special game B (see step S 222  to step S 223 ). 
     Furthermore, the slot machine  10  according to the first embodiment is configured such that, when five odds-change symbols are rearranged in the special game B, the special game B is terminated and the special game C is executed from the next game on condition that the disapproval order of the change has not been inputted (see step S 224  to step S 230 ). 
     Next, the special game C execution processing (see step S 500  in  FIG. 6 ) will be described by using  FIG. 10 . 
       FIG. 10  is a flowchart illustrating a subroutine of special game C execution processing. 
     First, the main CPU  41  executes the processing of step S 311  to step S 317 , and the processing is virtually the same processing as the processing of step S 111  to step S 117  in  FIG. 8 . Here, only a part different from the processing of step S 111  to step S 117  in  FIG. 8  will be described. 
     In step S 111  in  FIG. 8 , there has been described the case that the main CPU  41  determines whether or not the coins in number equal to or more than the special BET unit A (two coins, in the first embodiment) have been BET. On the other hand, in step S 311  in  FIG. 10 , the main CPU  41  determines whether or not the coins in number equal to or more than the special BET unit C (eight coins, in the first embodiment) have been BET. 
     Further, in step S 111  in  FIG. 8 , there has been described the case that the main CPU  41  determines that  40  coins have been BET when determining to have received the input signal outputted from the maximum BET switch  27 S. On the other hand, in step S 311  in  FIG. 10 , the main CPU  41  determines that 80 coins have been BET when determining to have received the input signal outputted from the maximum BET switch  27 S. 
     In step S 112  in  FIG. 8 , there has been described the case that the main CPU  41  subtracts the number of credits corresponding to the coins in number of 2N (=N×2) (N is the maximum integer satisfying 2N≦M). On the other hand, in step S 312  in  FIG. 10 , the main CPU  41  subtracts the number of credits corresponding to the coins in number of 8N (=N×8) (N is the maximum integer satisfying 8N≦M). 
     In step S 116  in  FIG. 8 , there has been described the case that the main CPU  41  refers to the special odds A data (see  FIG. 3B ) stored in the RAM  43  when determining the amount of payout. On the other hand, in step S 316  in  FIG. 10 , the main CPU  41  refers to the special odds C data (see  FIG. 3D ) stored in the RAM  43  when determining the amount of payout. 
     Next, when determining that the number of the odds-change symbol is three in step S 317 , the main CPU  41  clears the special odds C flag (step S 318 ) and sets the remaining number T C  of the special game C to T C =0 in the number-of-special-game-C storage area in the RAM  43  (step S 319 ). 
     Next, the main CPU  41  sets the special game A flag (step S 320 ). Then, the main CPU  41  set the remaining number T A  Of the special game A to T A =C A  (C A =10, in the first embodiment) (step S 321 ). 
     After executing the processing of step S 321 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not three in step S 317 , the main CPU  41  determines whether or not the number of the odds-change symbol is four (step S 322 ) 
     When determining that the number of the odds-change symbol is four, the main CPU  41  clears the special game C flag (step S 323 ) and sets the remaining number T C  of the special game C to T C =0 in the number-of-special-game-C storage area in the RAM  43 (step S 324 ). 
     Then, the main CPU  41  sets the special game B flag (step S 325 ). The main CPU  41  sets the remaining number T B  of the special game B to T B =C B  (C B =15, in the first embodiment) in the number-of-special-game-B storage area in the RAM  43  (step S 326 ). 
     After executing the processing in step S 326 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not four in step S 322 , the main CPU  41  determines whether or not the number of the odds-change symbol is five (step S 327 ). 
     When determining that the number of the odds-change symbol is five, the main CPU  41  sets the remaining number T C  of the special game C to T C =T C +C C −1 (C c =30, in the first embodiment) in the number-of-special-game-C storage area in the RAM  43 (step S 328 ). 
     After executing the processing of step S 328 , the main CPU  41  terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not five in step S 224 , the main CPU  41  sets the remaining number T C  of the special game C to T C =T C −1 (step S 329 ). 
     Next, the main CPU  41  determines whether or not the remaining number T B  of the special game B is T C =0 (step S 330 ). When determining that the remaining number T C  of the special game C is T C =0 in step S 330 , the main CPU  41  clears the special game flag C (step S 331 ). 
     When determining that the remaining number T C  of the special game C is not T C =0, or after executing the processing of step S 331 , the main CPU  41  terminates the present subroutine. 
     There has been described the special game C execution processing (see step S 500  in  FIG. 6 ) by using  FIG. 10 . 
     As above described, the slot machine  10  according to the first embodiment is configured such that, when three odds-change symbols are rearranged in the special game C, the special game C is terminated and the special game A is executed from the next game (see step S 317  to step S 321 ). In this case, the player cannot input the disapproval order of the change. 
     Further, the slot machine  10  according to the first embodiment is configured such that, when four odds-change symbols are rearranged in the special game C, the special game C is terminated and the special game B is executed from the next game (see step S 322  to step S 326 ). In this case, the player cannot input the disapproval order of the change. 
     Furthermore, the slot machine  10  according to the first embodiment is configured such that, when five odds-change symbols are rearranged in the special game C, the remaining number of the special game C is increased (see step S 327  to step S 328 ). 
     Subsequently, there will be described activation processing (see step S 101  in  FIG. 6 ) by using  FIG. 11  to  FIG. 13 . 
       FIG. 11  is a flowchart illustrating a procedure of activation processing. This activation processing is the processing conducted by the mother board  40  and the gaming board  50 . It should be noted that the memory card  53  is inserted into the card slot  53 S in the gaming board  50 , and the GAL  54  is mounted onto the IC socket  54 S. 
     First, when a power switch is turned on (power is turned on) in the power supply unit  45 , the mother board  40  and the gaming board  50  are activated (steps S 1 - 1 , S 2 - 1 ). In activation of the mother board  40  and the gaming board  50 , individual processing is respectively executed in parallel. Namely, in the gaming board  50 , the CPU  51  reads the auxiliary authentication program stored in the boot ROM  52 , and conducts auxiliary authentication according to the read auxiliary authentication program, to previously check and prove that the authentication program is not falsified before loading the program to the mother board  40  (step S 2 - 2 ). Meanwhile, in the mother board  40 , the main CPU  41  executes the BIOS stored in the ROM  42 , and expands compressed data which is incorporated in the BIOS into the RAM  43  (step S 1 - 2 ). The main CPU  41  then executes the BIOS expanded into the RAM  43  to diagnose and initialize a variety of peripheral devices (step S 1 - 3 ). The processing of step S 1 - 3  will be specifically described later with reference to  FIG. 12 . 
     Since the ROM  55  of the gaming board  50  is connected to the main CPU  41  via the PCI bus, the main CPU  41  reads the authentication program stored in the ROM  55 , and stores the read authentication program into the RAM  43  (step S 1 - 4 ). At this time, according to the standard BIOS function of BIOS, the main CPU  41  takes a checksum by ADDSUM system (normal checking system) and stores the authentication program into the RAM  43 , while conducting processing for confirming whether or not the storage is certainly conducted. 
     Next, after confirming what is connected to the IDE bus, the main CPU  41  accesses, via the IDE bus, the memory card  53  inserted in the card slot  53 S, to read a game program or a game system program from the memory card  53 . In this case, the main CPU  41  reads data constituting the game program and the game system program by  4  bytes. Subsequently, the main CPU  41  conducts authentication to check and prove that the read game program and game system program have not been falsified, following the authentication program stored in the RAM  43  (step S 1 - 5 ). When this authentication processing is normally completed, the main CPU  41  writes and stores the game program and the game system program, which have been the authentication targets (which have been authenticated), into the RAM  43  (step S 1 - 6 ). Next, the main CPU  41  accesses, via the PCI bus, the GAL  54  mounted on the IC socket  54 S, reads payout ratio setting data from the GAL  54 , and writes and stores the data into the RAM  43  (step S 1 - 7 ). Subsequently, the main CPU  41  conducts processing for reading country identification information stored in the ROM  55  of the gaming board  50  via the PCI bus, and writes and stores the read country identification information into the RAM  43  (step S 1 - 8 ). 
     After conducting the above-mentioned processing, the main CPU  41  sequentially reads and executes the game program and the game system program, thereby execute insurance setting processing and game execution processing. 
       FIG. 12  is a chart illustrating a procedure of peripheral-device initialization processing. 
     First, the main CPU  41  diagnoses and initializes a reel-related device (step S 3 - 1 ). In this processing, the main CPU  41  sequentially transmits request signals to the index detecting circuit  65 , the position-change detecting circuit  71 , and the motor driving circuit  62 . Then, the main CPU  41  determines whether or not to have received predetermined response signals and conducts clearance of a predetermined storage area, and the like. 
     Next, the main CPU  41  diagnoses and initializes a display (step S 3 - 2 ). In this processing, the main CPU  41  transmits the request signal to the graphic board  68 . Then, the main CPU  41  determines whether or not to have received a predetermined response signal and conducts clearance of a predetermined storage area, and the like. 
     Next, the main CPU  41  diagnoses and initializes various types of input devices (step S 3 - 3 ). In this processing, the main CPU  41  transmits request signals to the input devices such as the spin switch  23 S, the change switch  24 S, the CASHOUT switch  25 S, the 1-BET switch  26 S, the maximum BET switch  27 S, and the touch panel  11 , and then determines whether or not to have received predetermined response signals. 
     Subsequently, the main CPU  41  diagnoses and initializes other peripheral devices connected to the main CPU  41  (step S 3 - 4 ). Then the present subroutine is terminated. 
     In the present embodiment, there has been described the case where the slot machine  10  is a stand-alone type slot machine. However, in the present invention, a plurality of slot machines may be connected to a central controller via a network and controlled by the central controller. 
       FIG. 13  is a chart illustrating a procedure of activation processing executed by the central controller shown in  FIG. 13 . 
     First, when the power switch is turned on (the power is turned on) in the power unit, a mother board is activated (step S 4 - 1 ). 
     In the mother board, a CPU executes a BIOS stored in a ROM so as to expand compressed data incorporated in the BIOS into a RAM (step S 4 - 2 ). Then, the CPU executes the BIOS expanded into the RAM, and then, diagnoses and initializes various types of peripheral devices such as a display (step S 4 - 3 ). 
     Next, the CPU executes initialization processing of each slot machine. In this processing, the CPU establishes a network connection between the central controller and each slot machine, and diagnoses if the network functions properly. 
     After the above-described processing, the CPU controls proceeding of the game executed in a plurality of the slot machines by reading and executing a game control program. 
     There has been described the first embodiment. 
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (A) in the present invention (claim  1 ). Further, steps of (*) correspond to the step (A) in the present invention (claim  9 ). 
     (*) Step S 14  in  FIG. 7 , Step S 114  in  FIG. 8 , Step S 214  in  FIG. 9 , and Step S 314  in  FIG. 10   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (B) and the processing (D) in the present invention (claim  1 ). Further, step of (*) corresponds to the step (B) and the step (D) in the present invention (claim  9 ). 
     (*) Step S 16  in  FIG. 7   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (C) and the processing (D) in the present invention (claim  1 ). Further, step of (*) corresponds to the step (C) and the step (D) in the present invention (claim  9 ). 
     (*) Step S 116  in  FIG. 8 , Step S 216  in  FIG. 9 , and Step S 316  in  FIG. 10   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (A) in the present invention (claim  4 ). Further, steps of (*) correspond to the step (A) in the present invention (claim  10 ). 
     (*) Step S 14  in  FIG. 7   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (B) and the processing (E) in the present invention (claim  4 ). Further, step of (*) corresponds to the step (B) and the step (E) in the present invention (claim  10 ). 
     (*) Step S 16  in  FIG. 7   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (C) in the present invention (claim  4 ). Further, steps of (*) correspond to the step (C) in the present invention (claim  10 ). 
     (*) Step S 114  in  FIG. 8 , Step S 214  in  FIG. 9 , and Step S 314  in  FIG. 10   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (D) and the processing (E) in the present invention (claim  4 ). Further, step of (*) corresponds to the step (D) and the step (E) in the present invention (claim  10 ). 
     (*) Step S 116  in  FIG. 8 , Step S 216  in  FIG. 9 , and Step S 316  in  FIG. 10   
     Further, when executing the following processing of (I) to (III) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (F) in the present invention (claim  5 ). 
     (I) step S 19 , step S 24 , and step S 29  in  FIG. 7   
     (II) step S 121  and step S 128  in  FIG. 8   
     (III) step S 226  in  FIG. 9   
     In the first embodiment, there has been described the case where the odds are changed when the number of the rearranged odds-change symbol is three, four, or five. Here, “(The number of the rearranged odds-change symbol) being 3, 4, or 5” corresponds to the predetermined condition of the present invention. The predetermined condition of the present invention is not limited to this example, and an arbitrary number can be adopted. Further, the predetermined condition may be set to be “(The number of the odds-change symbol stop-displayed) being equal to or more than the predetermined number”. Further, the numbers according to the predetermined condition are not required to be consecutive numbers as in the first embodiment. For example, the predetermined condition may be “2, 4, or the number equal to or more than 6”. 
     Further, in the first embodiment, there has been described the case where the odds are changed, when the odds-change symbols in the predetermined number (3, 4, or 5) are rearranged, from the game subsequent to the game in which the odds-change symbols in the predetermined number are rearranged. However, in the present invention, a timing to change the odds is not particularly limited. The timing may be “when the games in the predetermined number are executed”. In this case, it is preferable to adopt a comparatively big number as the predetermined number of the game. This is because that adopting such a number can make the player have a motivation to continue playing the game until the odds are changed. Accordingly, it is possible that the player plays the game for a long time. 
     Furthermore, the slot machine may be configured such that the player can change the odds at an arbitrary timing by operating the input device. 
     In the first embodiment, the special odds have been described as advantageous odds for the player compared to the normal odds. However, in the present invention, the special odds may be the disadvantageous odds for the player compared to the normal odds. Further, two types of the special odds may be set, that is, the special odds advantageous for the player compared to the normal odds and the special odds disadvantageous for the player compared to the normal odds. 
     Further, in the first embodiment, there has been described the case where the normal symbol comprises the scatter symbol. However, in the present invention, the normal symbol is not required to comprise the scatter symbol and the slot machine may be configured such that the payout is conducted when the stop-displayed normal symbols form a predetermined winning combination (prize) on a winning line. In this case, the normal odds and the special odds may be associated only with the types of the stop-displayed normal symbols and unrelated to the number of the stop-displayed normal symbol. 
     Furthermore, the normal odds and the special odds of the present invention are not required to be indicative of the numbers of coin-outs in the case that a single coin is BET as in the first embodiment, and may be indicative of the constant amount of payout unrelated to the amount of the BET game media. 
     Further, in the first embodiment, there has been described the case that, when the number of the rearranged odds-change symbol is the predetermined number (3, 4, or 5), the odds-change text image (see  FIG. 1B ) is displayed and the player can input the disapproval order of the change by touching the place on the touch panel  69  corresponding to the part of “HERE” of the odds-change text image  101 D. However, in the present invention, the occasion that the player can input the disapproval order of the change is not limited to this example. For example, the slot machine may be configured such that the player can input the disapproval order of change at an arbitrary timing. In this case, for example, the slot machine may be configured such that the player can input the disapproval order of change by pressing a button provided on the control panel. Further, the slot machine may be configured such that the processing according to the change in odds (for example, processing of step S 17  to step S 31  in  FIG. 7 ) is not to be conducted when the odds-change symbols in the predetermined number are rearranged in the case that the disapproval order of the change has been inputted in advance. 
     Further, in the first embodiment, there has been described the case that the odds can be changed even during the special game period. However, in the present invention, the odds may be not changed during the special game period even when the odds-change symbols are rearranged. 
     According to the slot machine  10  of the first embodiment, the odds are changed as triggered by the rearrangement of the odds-change symbols in the predetermined number (3, 4, or 5). Accordingly, it becomes possible to have a player enjoy the change of the odds and thus fully enjoy the game. 
     Further, since the odds are changed in the case that the odds-change symbols in the predetermined number have been rearranged, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the rearrangement of the odds-change symbols in the predetermined number, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     Further, according to the slot machine  10  of the first embodiment, the odds are changed in the case that the number of the odds-change symbol rearranged is three, four, or five. Accordingly, whether or not the number of odds-change symbol is in the range of three to five is of great concern for the player. Therefore, it is possible to have the player find great pleasure in counting the number of the odds-change symbol while playing the game. Consequently, it is possible to have the player fully enjoy the game. 
     According to the slot machine  10  of the first embodiment, in the case that the odds-change symbols in the predetermined number are rearranged, the odds in the game subsequent to the game in which the odds-change symbols in the predetermined number are rearranged are changed to the special odds corresponding to the number of the rearranged odds-change symbol. Namely, the changed odds can be varied according to the number of the rearranged odds-change symbol. Accordingly, it is possible to significantly increase the attention of the player on the number of the rearranged odds-change symbol. 
     Further, according to the slot machine  10  of the first embodiment, the BET unit (the minimum unit to BET) in the special game is bigger than the BET unit in the normal game. Accordingly, it is possible to have the player place a BET of the game medium in a big number, which leads to a profit increase of a recreation hall. Further, not only the odds, but also the BET unit is changed as triggered by the rearrangement of the odds-change symbols in the predetermined number. Accordingly, it is possible to provide an unpredictable element to the player and increase an interesting aspect of the game. Furthermore, since the player can acquire a big payout by placing a BET of the game medium in a big number under a condition of the increased BET unit, it is possible to increase the player&#39;s expectation for the payout. 
     Furthermore, according to the slot machine  10  of the first embodiment, the BET unit is changed to the special BET unit on condition that the disapproval order of the change has not been inputted. Namely, the player can prevent the increase in the BET unit by inputting the disapproval order of change. Accordingly, the player reluctant to BET the game media in a large number can continue the game based on the minimum BET unit. Consequently, it is possible to provide a sense of satisfaction to the player. 
     Moreover, according to the slot machine of the first embodiment, in the case that the disapproval order of the change is inputted, the odds are not changed. Therefore, in the case that the player wishes to change the odds while not wishing to change the BET unit, the player has choices, namely, changing the odds or not changing the BET unit. Concurrently, it is possible to have the player go through a process of trial and error in selecting either choice, and through such a process, the player can be absorbed in the game. 
     Further, according to the slot machine  10  of the first embodiment, the remaining number of the special game A increases when three odds-change symbols are rearranged in the special game A which is generated as triggered by the rearrangement of three odds-change symbols. The remaining number of the special game B increases when four odds-change symbols are rearranged in the special game B which is generated as triggered by the rearrangement of four odds-change symbols. The remaining number of the special game C increases when five odds-change symbols are rearranged in the special game C which is generated as triggered by the rearrangement of five odds-change symbols. 
     As thus described, according to the slot machine  10  of the first embodiment, when the odds-change symbols are rearranged in the same number as the number of the odds-change symbol in accordance with a generation condition of the special game, the remaining number of the special game increases. Further, the special odds are odds advantageous for the player compared to the normal odds. It is therefore possible to make the player have expectations for the rearrangement of the odds-change symbols in the same number as the number of odds-change symbols in accordance with the generation condition of the special game. 
     Further, according to the slot machine  10  of the first embodiment, when four odds-change symbols are rearranged in the special game A, the special game B may be executed from the next game. When five odds-change symbols are rearranged in the special game A, the special game C may be executed from the next game. When five odds-change symbols are rearranged in the special game B, the special game C may be executed from the next game. 
     As thus described, according to the slot machine  10  of the first embodiment, when odds-change symbols are rearranged, in a single special game, in the same number as the number of the odds-change symbol in accordance with a generation condition of another special game, another special game may be executed from the next game. In this case, another special game is a special game in which special odds are adopted which are relatively more advantageous for the player compared to the special odds in the single special game. 
     Hence it is possible to make the player have an expectation for a change in odds from the special odds in the single special game to the special odds in another special game (a change from the special odds A to the special odds B or to the special odds C, or a change from the special odds B to the special odds C). 
     Further, according to the slot machine  10  of the first embodiment, when three odds-change symbols are rearranged in the special game B, the special game B is terminated and the special game A will be executed from the next game. When three odds-change symbols are rearranged in the special game C, the special game C is terminated and the special game A will be executed from the next game. When four odds-change symbols are rearranged in the special game C, the special game C is terminated and the special game B will be played from the next game. 
     As thus described, according to the slot machine  10  of the first embodiment, when the odds-change symbols are rearranged, in a single special game, in the same number as the number of the odds-change symbol in accordance with a generation condition of another special game, another special game will be played from the next game. In this case, another special game is a special game in which special odds are used which are relatively more disadvantageous for the player compared to the special odds in the single special game. Furthermore, in this case, the player cannot input the disapproval order of the change. 
     Hence it is possible to make the player have a kind of fear in a change in odds from the special odds in the single special game to the special odds in another special game (a change from the special odds B to the special odds A, or a change from the special odds C to the special odds A or to the special odds B). It is thereby possible to provide a thrill to the player. 
     Further, according to the slot machine  10  of the first embodiment, with a slight difference in number of the rearranged odds-change symbols, the odds are changed to the special odds relatively advantageous for the player or to the special odds relatively disadvantageous for the player. Hence, such a slight difference in number of the rearranged odds-change symbols can greatly please or discourage the player, so as to make the player fluctuate between hopes and fears. It is thereby possible to make the player absorbed in the game. 
     Second embodiment 
     In the first embodiment, there has been described the case that, when odds-change symbols are rearranged in the predetermined number (3, 4 or 5), odds can be changed from the game subsequent to the game in which the odds-change symbols are rearranged in the predetermined number. However, in the present invention, in the game in which the odds-change symbols are rearranged in the predetermined number, a payout based on the special odds may be conducted. 
     In the following, a slot machine  10  having such a configuration will be described. 
     It is to be noted that in the following, the same constituents as those of the slot machine  10  according to the first embodiment are described while provided with the same numerals. 
     Further, a description will be omitted as for a part in the second embodiment to which the description in the first embodiment is applicable. 
       FIG. 14  is a flowchart illustrating a subroutine of slot machine game execution processing according to the second embodiment. 
     First, the main CPU  41  executes processing of step S 411  to step S 415 . However, since the processing is same as the processing of step S 11  to step S 15  in  FIG. 7 , the description thereof is omitted here. 
     When determining in step S 415  that a prize has not been established, the main CPU  41  terminates the present subroutine. On the other hand, when determining in step S 415  that a prize has been established, the main CPU  41  executes payout processing (step S 416 ), and terminates the present subroutine. 
     Next, the payout processing will be described by using  FIG. 15 . 
       FIG. 15  is a flowchart illustrating a subroutine of payout processing according to the second embodiment. 
     First, the main CPU  41  determines whether or not the number of the rearranged odds-change symbol in step S 414  is three (step S 421 ). 
     When determining that the number of the odds-change symbol is three, the main CPU  41  determines the amount of payout based on the type and the number of the normal symbol rearranged in step S 414  with reference to the special odds A data (see  FIG. 3B ) stored in the RAM  43  (step S 422 ). 
     The main CPU  41  then executes processing in accordance with payout of the coin in amount corresponding to the determined amount of payout (step S 428 ) and terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not three, the main CPU  41  determines whether or not the number of odds-change symbol is four (step S 423 ). 
     When determining that the number of the odds-change symbol is four, the main CPU  41  determines the amount of payout based on the type and the number of the normal symbol rearranged in step S 414  with reference to the special odds B data (see  FIG. 3C ) stored in the RAM  43  (step S 424 ). 
     The main CPU  41  then executes processing in accordance with payout of the coin in amount corresponding to the determined amount of payout (step S 428 ) and terminates the present subroutine. 
     When determining that the number of odds-change symbol is not four, the main CPU  41  determines whether or not the number of odds-change symbol is five (step S 425 ). 
     When determining that the number of the odds-change symbol is five, the main CPU  41  determines the amount of payout based on the type and the number of the normal symbol rearranged in step S 414  with reference to the special odds C data (see  FIG. 3D ) stored in the RAM  43  (step S 426 ). 
     The main CPU  41  then executes processing in accordance with payout of the coin in amount corresponding to the determined amount of payout (step S 428 ) and terminates the present subroutine. 
     When determining that the number of the odds-change symbol is not five, the main CPU  41  determines the amount of payout based on the type and the number of the normal symbol rearranged in step S 414  with reference to the normal odds data (see  FIG. 3A ) stored in the RAM  43  (step S 427 ). 
     The main CPU  41  then executes processing in accordance with payout of the coin in amount corresponding to the determined amount of payout (step S 428 ) and terminates the present subroutine. 
     There has been described the second embodiment. 
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (A) in the present invention (claim  6 ). Further, steps of (*) correspond to the step (A) in the present invention (claim  11 ). 
     (*) Step S 414  in  FIG. 14   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (B) in the present invention (claim  6 ). Further, step of (*) corresponds to the step (B) in the present invention (claim  11 ). 
     (*) Step S 427  in  FIG. 15   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (C) in the present invention (claim  6 ). Further, step of (*) corresponds to the step (C) in the present invention (claim  11 ). 
     (*) Step S 422 , Step S 424 , and Step S 426  in  FIG. 15   
     When executing the following processing of (*) in cooperation, the main CPU  41  and the ROM  42  and the RAM  43  serve as the controller for executing the processing (D) in the present invention (claim  6 ). Further, steps of (*) correspond to the step (D) in the present invention (claim  11 ). 
     (*) Step S 428  in  FIG. 15   
     According to the slot machine  10  of the second embodiment, the payout is conducted based on the special odds different from the normal odds as triggered by the rearrangement of the odds-change symbols in the predetermined number (3, 4, or 5). Accordingly, it becomes possible to have a player enjoy the variety of the odds and thus fully enjoy the game. 
     Further, since the payout is conducted based on the special odds in the case that the odds-change symbols in the predetermined number have been rearranged, it is possible to make the player have an interest and an attention on the odds-change symbol. Furthermore, it is possible to have the player play the game with a high expectation for the rearrangement of the odds-change symbols in the predetermined number, and the player can be absorbed in the game. Consequently, it is possible to provide a game that the player hardly gets tired even playing for a long time. 
     According to the slot machine  10  of the second embodiment, the payout is conducted based on the special odds in the case that the number of the rearranged odds-change symbol is three, four, or five. Accordingly, whether or not the number of the rearranged odds-change symbol is in the range of three to five is of great concern for the player. Therefore, it is possible to have the player greatly enjoy counting the number of the odds-change symbol while playing the game. Consequently, it is possible to he player fully enjoy the game. 
     Further, according to the slot machine  10  of the second embodiment, a payout may be conducted based on the special odds different in accordance with the number of the rearranged odds-change symbol. It is therefore possible to significantly increase the player&#39;s interest in the number of rearranged odds-change symbols. 
     In the first and second embodiments described above, there have been described the cases where symbols are rearranged in the symbol matrix SM of the lower image display panel  16  (the slot machine  10  is a so-called a video slot machine). However, the slot machine according to the present invention may be configured to stop-display symbols using so-called mechanical reels. 
       FIG. 16  is a perspective view illustrating the general appearance of a slot machine according to another embodiment. 
     In the following description, the components corresponding to those of the slot machine  10  will be designated by the same reference numerals. 
     Further, the slot machine  310  has substantially the same external appearance, the same circuit structure and the like as those of the slot machine  10  and also executes substantially the same flowcharts as those executed by the slot machine  10 , except that it employs mechanical reels, and, therefore, only the mechanical reels will be described herein. 
     As illustrated in  FIG. 16 , five reels  314  ( 314 A,  314 B,  314 C,  314 D and  314 E) are rotatably provided within a cabinet  11 . On the outer peripheral surfaces of the reels  314 A,  314 B,  314 C,  314 D and  314 E, there are drawn symbol sequences constituted by normal symbols such as “RIBBON”, “HEART”, “STAR”, “MOON”, “SUN”, “JEWEL”, “CROWN”, and “SMILE”, and the odds-change symbol. 
     At the center portion of the lower image display panel  16 , there is provided a display area  328  for displaying the symbols. Within the display area  328 , there are formed five display windows  315  ( 315 A,  315 B,  315 C,  315 D and  315 E) visible through their back surfaces. Further, the symbols drawn on the outer peripheral surfaces of the reels  314 A,  314 B,  314 C,  314 D and  314 E are displayed on a three-by-three basis, through the display windows  315 A,  315 B,  315 C,  315 D and  315 E. 
     Although the present invention has been described with reference to embodiments thereof, these embodiments merely illustrate concrete examples, not restrict the present invention. The concrete structures of respective means and the like can be designed and changed as required. Furthermore, there have been merely described most preferable effects of the present invention, as the effects of the present invention, in the embodiments of the present invention. The effects of the present invention are not limited to those described in the embodiments of the present invention. 
     Further, in the aforementioned detailed description, characteristic portions have been mainly described, for ease of understanding the present invention. The present invention is not limited to the embodiments described in the aforementioned detailed description, but can be also applied to other embodiments over a wider range of applications. Further, the terms and phrases used in the present specification have been used for clearly describing the present invention, not for limiting the interpretation of the present invention. Further, those skilled in the art will easily conceive other structures, systems, methods and the like which are included in the concept of the present invention, from the concept of the present invention described in the present specification. Accordingly, the description of the claims is intended to include equivalent structures that fall within the technical scope of the invention. Further, the abstract aims at enabling engineers and the like who belong to the present technical field but are not familiar with the patent office and public institutions, the patent, law terms and technical terms to immediately understand the technical content and the essence of the present application through brief studies. Accordingly, the abstract is not intended to restrict the scope of the invention which should be evaluated from the description of the claims. It is desirable that literatures and the like which have been already disclosed are sufficiently studied and understood, in order to sufficiently understand the objects of the present invention and the specific effects of the present invention. 
     In the aforementioned detailed description, there have been described processing to be executed by computers. The aforementioned description and expressions have been described for the sake of enabling those skilled in the art to understand the present invention most effectively. In the present specification, each step for deriving a single result should be understood to be self-consistent processing. Further, each step includes transmission, reception, recording and the like of electric or magnetic signals. Although, in the processing at each step, such signals have been expressed as bits, values, symbols, characters, terms, numerical characters and the like, it should be noticed that they have been merely used for convenience of description. Further, although the processing at each step was described using expressions common to human behaviors in some cases, the processing described in the present specification are to be executed by various types of devices, in principle. Further, other structures required for conducting each step will be apparent from the aforementioned description.