This study investigated in what kind of situations a teacher had used "laughter" during instruction. In order to examine the functions of laughter, the scenes where a teacher performed "laughter" in the novice Japanese class were analyzed. The data were obtained from novice Japanese class with one Japanese teacher and eight learners. From the result, it was revealed that there are three situations where the teacher used laughter:1)the situation that the teacher reacted to learners making others to laugh, 2)the situation that the teacher reacted to learners who didn't make others to laugh, 3)the situation that the teacher laughed in her own. As a result of having analyzed three types of laughter in detail, we suggest the three possibilities of reasons that the teacher used laughter; 1) to make the atmosphere of the class better, 2) to avoid face threatening act of both the teacher and students, 3) to help students easily follow the class.