This article is aimed at focusing on the proper use of synonyms, which are considered to be one of the most important factors for intermediate or above Japanese learners, and surveying how pairs of synonyms of Korean and Japanese adverbs - ‘Gajang’ and ‘Jeil’ in Korean and ‘Mottomo’ and ‘Ichiban’ in Japanese ？ are utilized in Korean and Japanese newspaper articles. According to the results, ‘Gajang’ and ‘Mottomo’ are usually used as a literary style in a wide variety of genres, along with literary genres including politics and economy, whereas ‘Jeil’ and ‘Ichiban’ are frequently used as a colloquial style in ordinary genres including sports and entertainment. However, compared with ‘Gajang’ and ‘Jeil’ in Korean, ‘Mottomo’ and ‘Ichiban’ in Japanese are thought to be in huge conflict with each other as literary/official language and colloquial/everyday language.