Out of entire salivary tumor, 1.7% are malignant lymphoma developed in salivary gland and it is usually mucosa associated lymphoid tissue (MALT) lymphoma developed in salivary gland. In the case of Non-Hodgkin lymphoma, the most frequently involved extanodal sites of diffuse large B cell lymphoma are bone, skin, thyroid, gastrointestinal tract, and lung. Development in salivary gland is very rare. A 69 years old male patient who have found Lt. submandibular gland (SMG) mass a month ago is suspected of malignancy from his FNA result, so histologic exam by SMG resection was operated. According to histopathologic exam, large B cell lymphocyte infiltratration were generally shown as diffuse and lymphoepitheliallesion were not found. In immunostaining, CD79a showed positive and CD3, CAM5.2 showed negative which diagnosed as diffuse large B cell lymphoma. As Ann Arbor stage I, CEOP-B chemotherapy was used 3 times as treatment without any recurrence. In the case of malignant lymphoma in salivary gland, it develops as painless mass in ipsilateral side. If found in parotid gland, it is rare to have facial nerve falsy and pathologically diagnosed as lymphocytes of abnormal type of monoclonal immunostaining must be provided as evidence. Combined therapy is known as most effective treatment for intermediate grade.