This paper is to investigate the factors which internally or externally influence the Korean EFL adult learners’ use of the English articles. To achieve this, this study will look into what aspect of article use is the most difficult or the least for the Korean EFL learners and what factors influence their article use internally and externally. To examine them, this study scrutinized the English article use of 78 Korean EFL adult learners. While practicing this procedure, this study gained the following findings: the English article use of Korean EFL adult learners was affected internally by the countability of nouns and externally the syntactic difference between English and their frist language and their English proficiency. By doing these matters, we will be sure that what has been suggested can be offered as a source for Korean EFL learners to overcome the difficulty in attaining the English articles.