The purpose of this study is to investigate object and significance in Korean lexical education. The basic assumption of this study is that lexical education should be learner’s improvements of lexical competence. Learners improvements of lexical competence have something to do with improvements of learner’s mental lexicon. In chapter 2, we deal with significance in Korean lexical education. In chapter 3, we deals with relations between object of lexical education and learner’s mental lexicon. In chapter 4, we deal with aspects of lexical education in Korean education, especially object of lexical education, contents of lexical education, period or time of lexical education, methods of lexical education and so on. To explain these issues, we give careful consideration to institution of curriculum, textbooks and so on. As a consequence, we comprehend deeply the object and significance of lexical education in Korean education.