The Exploratorium, founded by Frank Oppenheimer, has been regarded as one of the origins of hands-on 'science' museums, while its unique exhibition rationale described in its title 'the museum of science, art and human perception,' shows that it is not necessarily a simple 'science museum.' Why has it been perceived as a museum, not of 'science, art and human perception,' but of 'science'? In order to explore the question, the present study examined how the Exploratorium's exhibition rationale was reflected in the exhibition, 'Exploratorium in Japan' held in 1989. Through an extended examination of the exhibit selection process using a collection of recorded documents from the Japanese side as well as an archive from Exploratorium's official management record (US side), no concrete and detailed discussion on the exhibition rationale and/or exhibit policy between the two sides was found to have happened during the negotiation process.