Hypothesis: We assumed two hours or lower duration between dinner and bedtime influence on increasing HbA1c level. Data collection: We collected three year health check-up data of middle aged and elderly Japanese in the community. Lifestyle factors include two hour duration between dinner and bedtime, fast eating, skipping breakfast, eating midnight snack, smoking, alcohol drinking, doing exercise, active lifestyle, and biophysical status were age, height, weight, BMI, waist circumference, blood components, and medical examination history. Result and interpretation: The duration between dinner and bedtime did not significantly affect on HbA1c level. The finding was variated by some lifestyle factors such as smoking and alcohol drinking, and BMI status. Rather than duration of dinner and bedtime, people should pay more attention to healthy components of last and adequate sleeping time for maintaining stable metabolic process.