People sometimes experience Aha! moments when solving problems, but the nature of these experiences and their sources have not been extensively explored. According to the processing fluency framework, an Aha! experience may be considered a result of a sudden increase in processing fluency. Based on this, we suggested that Aha judgements could be affected by the misattribution of processing fluency. In two experiments, we tested this hypothesis using remote associate problems with mirrored letters. The first experiment demonstrated that problems with mirrored letters are less likely to be judged as solvable compared to normally written problems, suggesting that mirroring letters reduces processing fluency. In the second experiment, participants judged Aha! experiences in response to solutions' presentation. Our findings indicate that participants were more likely to report an Aha!-like comprehension when the mirrored writing changed to normal at the moment of the correct solution presentation. That is, a sudden increase in perceptual fluency led to higher chances of experiencing Aha! moments. These results indicate that Aha! experiences can be affected by fluency misattribution.