A 91-year-old man was diagnosed with Merkel cell carcinoma after removal of a mass about 1 cm in diameter from the right upper eyelid on August 5, 201X. Curative surgery was recommended, but the patient declined. Lymph node metastases to the right lateral angle of the eye and in front of the right ear, and cancer pain in the stump recurrence manifested. Accordingly, irradiation of the right upper eyelid was started from October 3 at 2.5Gy/fraction, and the right lateral corneal lymph nodes were included from October 11, ending at 35 Gy in 14 fractions. From November 22,irradiation of the lymph node metastasisin front of the right ear was started, ending at 32. 5 Gy in 13 fractions. During irradiation, cancer pain was alleviated with opioids. Stump recurrence and lymph node metastases were decreased in size, and Computed Tomography indiated complete response. Radiation monotherapy of Merkel cell carcinoma appears to offer a treatment that should be proactively applied when curative surgery proves difficult or not desired by the patient. Use of opioids during radiotherapy may improve quality of life and enhance the therapeutic effect