In the diabetic medical practice, continuous glucose monitoring (CGM) has been recently used with beneficial efficacy. Authors have continued women’s medical care and research on Calorie Restriction (CR) and Low Carbohydrate Diet (LCD), and developed medical and social LCD movement by Japan LCD Promotion Association (JLCDPA). In this study, a diabetic female case with remarkable improving effect is shown using CGM and LCD. The case is 27 years-old female with type 2 diabetes mellitus (T2DM). She has been pregnant and on multiple daily insulin injection (MDI) with insulin 48 units/day in the university hospital. She was on this treatment until 28th weeks with no preeclampsia symptoms, and hoped to change the treatment of LCD. She came to our women’s clinic with the current data of weight 101kg, BMI 37.1 and HbA1c 7.0%. By application of FreeStyle Libre (Abbott, USA), her glucose variability showed around 160mg/dL with some episodes of hyperglycemia. The meal was changed from CR to LCD after 29th week, then insulin administration could be discontinued in 10 days. This glucose variability showed remarkable efficacy for combination of LCD and CGM. These results would become basal and reference data and contribute to the development of future research