We face many problems in everyday life and solve them. In this study, we investigate insight problem solving. Insight problems solving is known as problem solving accompanied with 'Aha! experience' in Gestalt psychology. Insight problem solving is characterized by sudden solution without notice. For this reason, it is suggested that this specific feeling such as sudden finding may be brought about by subconscious cognitive processing. But the mechanism of the process is not still clear. In this study, we try to investigate factors that affect the subconscious processes using the slot machine task (Miwa & Matsushita, 2000). In Experiment 1, the participants engaged in analogical problem solving in which first they were required to solve a source task as a cue stimulus and then engaged in the slot machine task as a target task. From the viewpoint of the ratio of successful participants, as Gick & Holyoak (1983) suggested, the participants who were not informed of the relationship between the source and target tasks tended not to reach the solution in the target task. This is known as the difficulty of automatic analogical reasoning. On the other hand, from the viewpoint of the number of trials needed for the solution, the successful participants who had experienced the source task reached the solution faster than those who had not. In addition, almost all of them did not notice the relationship between the two tasks. This result implies that some type of subconscious processes advances the insight problem solving. In Experiment 2, we used the priming method that has been used in priming studies to investigate subconscious cognitive processes. According to Experiment 1, the participants engaged in the identical analogical problem solving. In Experiment 2, we set up two experimental conditions: one in which subliminal stimulus was presented when the target task was solved and the other in which such a stimulus was not presented. The result indicated that there were no differences in the performance between the two groups. Our conclusion suggests: (1) the analogical cues are effective in solving insight problem where some types of subconscious cognitive processes advance the solution, and (2) the semantic cognitive processing is need to be activated for promoting such subconscious cognitive processes.