Purpose: An osteoma is one of the common benign tumors that penetrate the nasal portion, paranasal and frontal sinus. This tumor is mostly found by radiation test accidentally, however in rare cases; it can be found to be touched or with its symptoms as the tumor grows. We report this case since we found and healed the benign tumor which was affecting orbit and the both sides of fronal sinus. Methods: A 19 year old female patient visited to our hospital due to the mass on her forehead. The symptoms began 3 years ago but no special symptom was found except for touchable mass. She was diagnosed as the osteoma of superior orbital parts and both sides of frontal sinus using X-ray and CT scanning. The size of osteoma was $5{ imes}2.5{ imes}3.5;cm$ and indicated the patterns penetrated to the right side of orbital region. The osteoma excision was conducted with coronal incision and wide area of defect part in frontal sinus and superior orbital part were reconstructed by cranial bone graft and resorbable fixation plates. Results: The patient recovered without any postoperative infections or complications and symptoms. Dysaesthesia was found on her frontal area but improved in 1 month after the surgery. Conclusion: The occurrences of osteoma in frontal sinus are rare and can be treated with conservative methods if there are no infections and symptoms. We report this case since we found the benign tumor, which was affecting orbit and the both sides of fronal sinus and healed it with coronal resectomy without any complications.