This paper analyzed dialogues in high school Japanese textbooks published according to the 2007 revised national curriculum, based on sociolinguistic variables and dialogue structure rules. The findings are as follows: first, the analysis of the construction of the textbooks shows that dialogues take place most frequently in the areas of speaking and listening while dialogues appear in the area of writing at the lowest rate of 10 percent. Secondly, the analysis of the dialogues based on sociolinguistic variables shows that in most textbooks dialogues take place in various places such as houses, stores, schools, streets and restaurants, but places in some dialogues are not identified. As for the topics of the dialogues, leisure and hobbies, traveling, food, and giving directions are the most common topics. There are many dialogues which do not have any specific topics but include basic expressions for communication. Moreover, most dialogues do not identify clear relation among participants, which needs to be improved. Lastly, the analysis of the dialogue structure rules finds that as for the length of the dialogue, one or two rounds of exchanging of talks are the most common and in the most cases the format of taking turns of speaking is the set of A-B-A-B, which indicates that the dialogues are very simply structured. The cases of adjacent pairs are mainly focused on question and answer sets. From the analyses, it is found that if we figure out the characteristics and problems of dialogues appearing in current Japanese textbooks and include the sociolinguistic variables and diverse dialogue structure rules into the dialogues to construct more authentic dialogues, the dialogues provided in the high school Japanese textbooks will be a lot more helpful to improve the learners’ communicative ability.