The goal of this research is to investigate the meditation experiences of Zen practitioners by adopting a qualitative analysis. Using the results obtained with this method, I will explain how the revelation of a Zen meditator about the true nature of emptiness can be one of the elements of an effective psychotherapy. The subjects involved in this research are seventeen Buddhist Zen meditators. Their ages range from 25 to 65, on average they have 7 years of meditation experiences. First of all, the subjects were asked to provide their diaries describing anywhere from one to ten meditation experiences. Then, the interviews were conducted, and the results were organized into notes. I, while repeatedly reading the interview notes, felt myself released and let myself be questioned by the topic of the interview. Based on my background of knowledge, I had responses to the questions of the interview. Using this kind of investigative method, the main theme subtly concealed in the data directed me, and took a shape of its own. It became clear that the main theme of the study is that the revelation attained about the nature of emptiness is one of the elements leading meditators to psychological health. From the data accumulated from the seventeen research subjects, this research yielded the following results: 1) In Zen meditation, because of the level of concentration achieved, mental stimulation was reduced, emotions became more even and steady, and one could consciously regulate the circulation of bodily energy. Following such regulation, Zen practitioners’ emotions became purified, their physical sensitivity increased accordingly, as did their ability to be aware of their mental states. Self-control was increased, and subjects could concentrate themselves easily. Powers of understanding were advanced, and the ability to accept things as they are was raised. 2) Through meditation, Zen practitioners realized that things are always multifaceted, and never with any single and independent nature. They realized the inconstancy of their thoughts and feelings, as well as how attachment leads to the production of pain. Finally, they had revelations about the nature of emptiness. 3) Based upon their revelations of the nature of emptiness, meditators were able to let go of their attachments to things, even to the point where they were able to abandon the searches their minds were constantly engaged in. They concentrated upon their method of meditation, quieting their minds and sitting. Thus were meditators able to enjoy many psychological benefits produced by Zen sitting meditation. 4) Based on meditation, Zen cultivators were able to transform the emotions that result from stimulation and achieve a sense of stability, of standing in the center. For this reason, cultivators were able to look at things from an objective point of view without being bothered by their emotions. Based on their revelations of the nature of emptiness, on the other hand, cultivators were able to regard things directly from an objective perspective and reduce the emotions arisen from atta