The main purpose of this study is to analyze the Japanese learners’ pronunciation of Korean syllable final nasal based on the phonological process of alternation, deletion and insertion. The characteristic aspect of Japanese learners’ pronunciation generally occurs in the confusion between the group of Korean syllable final nasals. It can be represented as a phonological process of alternation which is caused by the place assimilation. In some cases, on the other hand, the deletion and insertion that are closely related occur pronunciation of Korean syllable final nasals. Some Japanese learners tend to delete the Korean velar nasal in syllable final position due to the non-applying syllable structure constraint of Korean prohibits the distribution of syllable initial /ŋ/. In similar cases, Japanese learners tend to insert the Korean velar obstruent in syllable final position due to the place assimilation and the reduplication with following syllable initial consonant. These phenomena show the character of Japanese syllable final /N/ which is called archiphoneme.