There have been very few studies on the prevalence and severity of acne scars in Japanese patients. The aim of the present study was to investigate the prevalence of acne scars and their impact on the quality of life (QOL) in Japanese acne patients. Acne scars were classified as mini-scars (atrophic scars of ≥0.5 and <2 mm in diameter) atrophic scars (≥2 mm in diameter), and hypertrophic scars. The severity of acne and acne scars were evaluated. The background of patients and their QOL in relation to acne were assessed. Of 240 subjects, 218 (90.8%) had scars. All patients with scars had mini-scars; 61.2% and 14.2% of 240 had atrophic scars and hypertrophic scars, respectively. Severe scarring was found in patients who had experienced severe acne symptoms, although 15.0% of patients with scars had experienced only mild acne symptoms. The total Dermatology Life Quality Index score was significantly higher in patients with scars than in patients without scars (5.9 ± 4.4 vs 4.2 ± 4.1). Almost all the patients had small atrophic scars with a diameter of 0.5 or more and less than 2 mm, which we have termed "mini-scars". Acne scars had a negative impact on patient QOL. Early initiation of treatment is recommended to avoid acne scars.