This Study is to Assess the Efficacy of Difamilast Ointment in Mild to Moderate Atopic Dermatitis(AD)

Important Inclusion Criteria: 1. Subjects who are male or female ≥2 years of age 2. Subjects and/or their parent(s)/legal guardian(s) (if subject is under the legal age of consent) provide written informed consent in accordance with federal and/or local laws prior to the conduct of any study-related procedures. 3. Subjects who have a diagnosis of AD based on the American Academy of Dermatology AD diagnostic criteria 4. Subjects who have had a diagnosis of AD for at least 6 months prior to Screening visit 5. Subjects who have AD involvement ≥5% to ≤40% of treatable Body Surface Area (BSA) excluding scalp 6. Subjects who have an AD Severity of mild (2) or moderate (3) as measured by the IGA of AD Severity score at screening and baseline visit Important Exclusion Criteria: 1. Female subjects who are pregnant or breastfeeding or who plan to become pregnant during the study and through 90 days after the last dose of study drug 2. Subjects who have evidence of spontaneous clearance of AD between screening and baseline visits 3. Subjects who have a history of unstable AD as assessed by the Investigator. Unstable AD is defined as disease flares occurring within 4 weeks prior to baseline visit 4. Subjects who have an active or acute skin infection (eg, herpes simplex, herpes zoster, and chicken pox) and/or clinically infected AD 5. Subject with greater than mild depression and suicidal ideation prior to screening or between screening and baseline visits 6. Subjects who have a known history of alcohol abuse or illicit drugs within 6 months prior to screening Etc.,