Employing Conversation Analysis (CA) as a research framework, this study explores argument in Japanese in intercultural marriage. Previous studies in intercultural communication have examined only cultural differences between Japanese and Americans to discuss communication problems under the assumption that cultural differences are the source of the problems in intercultural communication. This study looks into an extended single case of naturally-occurring interaction between an American husband and a Japanese wife in order to examine the process of how a dinner table conversation develops into an argument, focusing in turn on the opening, developing, and closing stages. If communication problems in intercultural marriage are due to a couple’s different cultural backgrounds, this should be recognizable through analyzing their interaction. However, this study identified that the argument occurred when the husband and the wife had contested claims on a language-related issue that had no relation to the cultural differences between them.