The purpose of the present study was to investigate how the degree of self-participation and not mental, but real, representation influences preschool children's remembering their own false-beliefs. It has already demonstrated that the rate of children correctly remembering their own false-beliefs increases under the procedure that they post a card of a representation. They thought the reasons why participation in the task and the real representations have an influence. In an experiment, I observed how three- to five-year old children (n=53) reacted to tasks equivalent to "Smarties" tasks. The effects of the children's participation in the tasks were controlled in stages, as were the real representations by stages. The results showed that children less than four and a half years old were not able to remember their own false-beliefs even if their participation was high and there were real representations. Children four and a half years old and over, however, had developed a meta-representation ability to deal with mental states as representations. However, development of meta-representation ability only was insufficient for children's remembering of their own false-beliefs. This indicates children require specific self-participation in the tasks or existence of real representations.