Actinomycosis is a rare acute-to-chronic bacterial infection caused by Actinomyces. A 7-year-old healthy girl presented with left-sided nasal obstruction and purulent discharge. She had no special medical or trauma history, and the symptoms developed gradually after severe vomiting one month prior to the visit. Nasal endoscopy revealed white-black-colored cheesy material that appeared as a foreign body or fungal material in the left nasal cavity. The lesion was completely removed endoscopically under local anesthesia. The patient was prescribed only a topical antibiotic ointment without any additional systemic antibiotics. She was diagnosed with actinomycosis based on histopathological examination after a few days. There was no recurrence at six months post-procedure. The common treatment for actinomycosis is surgical removal and a systemic antibiotic therapy. However, this case was successful with complete surgical removal and only a short-term topical antibiotic ointment therapy. Therefore, the treatment for actinomycosis should differ based on clinical characteristics and the patient’s condition.