Facial nerve schwannomas (FNSs) are usually painless, slow-growing, and without specific symptoms, so that early diagnosis may be difficult. They are particularly liable to being misdiagnosed as parotid gland origin benign tumor before surgery, which can lead to unnecessary parotidectomy or unexpected facial nerve injury. To prevent these complications, it is important that the correct diagnosis is performed at least in intraoperative time. When an adhesion between the mass and the facial nerve is exist or when electrical stimulation of the mass triggers facial movement, FNS is highly suggested diagnosis. In such cases, frozen section analysis should always be performed. In this case, the pre-operative diagnosis from clinical examination and MRI was pleomorphic adenoma. However, intraoperative features led us to suspect that the mass originated from facial nerves, and intraoperative frozen section analysis yielded results consistent with a schwannoma. Based on this intraoperative diagnosis, we carried out a successful conservative treatment with preservation of facial nerve.