Concept map is a useful tool for learners to organize and represent knowledge. Kit-Build Method has been proposed as an approach to realize automatic diagnosis of the concept map. In this paper, we report a practical use of the concept map with Kit-Build Method (KB map) in an elementary school in science learning. In this use, a teacher gave an additional lecture by using the result of the diagnosis of learner’s maps as feedback for the maps. Through the practical use, we have confirmed the effectiveness of the diagnosis of learners’ comprehension and feedback for them with KB map.