The purpose of this article is to show characteristics of complaints of Korean native speakers (KNs), Korean learners (primary, intermediate, and high class) of Japanese language of (KLs), and Japanese native speakers (JNs). When fourteen displeased situations happening occasionally in daily life were given to them, for their complaints about the situations, the degree of complaints and the expression behavior of complaints were investigated. Particularly the complaints by speech act were analyzed with a point of view on the use of strategy and the degree of face-threat (FT). The degree of complaints was higher in order of JNs>KLs>KNs. For the expression behavior of complaints, all of three group (KNs, KLs and JNs) tended to use speech act. For the strategy of complaints and the degree of FT, JNs tended to use strategy of lower degree of FT than that of KN. And KLs showed a tendency of interlanguage which was getting close to targeting language, using strategy of lower FT degree than that of mother language group (KNs) even at a primary class. These results give the following implications for the education of Japanese language for KLs. 1) As the most useful method to resolve the situations of complaints, JNs also use speech act, but JNs recognize the situations more seriously than KNs and their degree of complaints is higher. 2) Nevertheless, JNs are contrasted with KNs by that they would minimize the probable trouble with a person due to their complaints by selecting strategy of low FT degree.