Inclusion Criteria:  Male and female patients between 30 - 65 years old(based on birthdays) Type 2 Diabetes Mellitus patients Patients who have been taking three types of oral hypoglycemic agent for at least 12 weeks Patients whose selection test show HbA1c as 8 ~ 10% Patients who are willing to use the RT-CGM Patients who have signed the letter of consent  Exclusion Criteria:  Type 1 Diabetes Mellitus patients Gestational Diabetes patients Patients who have undergone continuous or intermittent insulin treatments for more than 7 days within 12 weeks from the selection test date. Patients who underwent oral or non-oral corticosteroid treatment for more than 7 continuous days 1 month before the selection test date. Patients with history of hyperplastic diabetic retinosis Patients with serious case of infection, scheduled for surgery, history of recent surgery, severe injury Patients with history of malignant tumor in five years Patients whose records show history of drug abuse or alcoholism within 12 weeks from the questionnaire, medical report and past treatment reports Female patients who are pregnant or breast -feeding Patients who are participating in other clinical researches other than the current clinical research or who have taken other clinical test drugs within 4 weeks Patients who are unfit to partake in this clinical research as determined by the researcher