Background: Demand for non-invasive body contouring has increased. High-intensity focused ultrasound (HIFU) induces coagulative necrosis of unwanted adipose tissue. Objectives: This study aimed to investigate the efficacy and safety of an HIFU device for abdominal body shaping. Methods: Adults (18-65 years) with a body mass index ≤ 30 kg/m2 and an abdominal subcutaneous fat tissue thickness ≥2.5 cm were enrolled for HIFU treatment at energy levels of 150 J/㎠ (first session) and 135 J/㎠ (second session). The primary endpoint was a change from baseline waist circumference at posttreatment week 8. Secondary efficacy endpoints were changes in body weight, waist/hip ratio, and fat thickness assessed by ultrasound or caliper, as well as the result of a fat CT scan. The Global Aesthetic Improvement Scale was evaluated by both investigators and subjects. Results: The primary assessment achieved statistical significance, showing a reduction of 3.43 cm in mean waist circumference. The treatment effect was cumulative, with a steady decrease in waist circumference and fat thickness. No serious adverse effects were observed during the follow-up period. Conclusion: HIFU is an effective and safe treatment modality for reducing waist circumference in non-obese individuals with focal fat accumulation.