The purpose of the present study was to investigate the facilitative factors for understanding "three prisoners problem (Ichikawa, 1988)". Ichikawa (1988) suggested that the difficulty of the problem arised from the conflict between the normative answer and intuitive judgment based on the subjective theorems. In his explanation, two levels of understanding were postulated. One is an intuitive understanding, and the other is a logical understanding. In this study, therefore, two different operations for facilitating these two levels of understanding were conducted. One was to ask a question supposed to guide the subjects to intuitive understanding, and the other was to explain how to solve the problem by presenting the Bayesian theorem or by presenting the isomorphic schematic representation proposed by Ichikawa (1989). The results indicated that both the guided question and the logical explanations facilitated the rated scores of understanding, and the logical explanations facilitated the percentages of correct responses in the transfer problems, whereas the guided question did not facilitate them. These findings were discussed in terms of the function of the subjective theorems in probability judgment.