This study investigated a subcutaneous injection anesthesia using 7 mg/kg alfaxalone following premedication with 0.2 mg/kg medetomidine and 2.5 mg/kg butorphanol in degus. Degus were lateral positioned after approximately 3 min and the sedative and anti-nociceptive effect lasted approximately 20 min. Using an oxygen mask, the percutaneous arterial oxygen saturation (SpO2) was maintained at 99%. The body temperature, heart rate, respiratory rate, and pulse rate were also maintained within a clinically satisfactory range. In degus under the subcutaneous injection anesthesia, a simulated intraoral treatment proceeded smoothly without resistance and flow-by oxygen supplementation reduced hypoxia (approximately SpO2 93%). Therefore, this subcutaneous injection anesthesia is considered to be a useful anesthesia protocol that allows intraoral treatment in degus.