In my presentation, I compare the “Organ Theory” and the “Intertemporal Bargaining Model” to consider which is more adequate as the model of will. The organ theory explains that will is an organ which overcomes short term reward if it is imminent and estimated higher than long term reward. On the other hand, G. Ainslie claims that will is not an organ but a type of bargaining situation. There seems to be a considerable discrepancy between the Intertemporal Bargaining Model and the Organ Theory about weakness of will. Weakness of will can be restricted in the Intertemporal Bargaining Model, while it is nonrestrictive in the Organ Theory. I suggest that we need not reject either of them because these two theories focus on the different aspects of weakness of will. The Organ Theory focuses on weakness of will on the same occasion, while the Intertemporal Bargaining Model focuses on that on different occasions. Therefore, the nonrestrictiveness of weakness of will in the Organ Theory does not contradict the restrictiveness of weakness of will in the Intertemporal Bargaining Model. These two theories are compatible as the model of will. In the response to my presentation, some people appreciated my view as unique, and also pointed out some ambiguities in my argument. The discussion with them was exciting and positive experience for me. I would like to take this opportunity to thank H. Tsutsui and all of people who were involved in this colloquium.