A monitoring device includes a transmitting unit, a receiving unit, and a determining unit. The transmitting unit transmits, to a plurality of base stations, instructions on mutual monitoring among the base stations. The receiving unit receives, from a base station that has detected abnormality of a base station serving as a monitoring target in accordance with the instruction among the base stations, information indicating a base station determined as having abnormality. The determining unit determines a level of a fault that has occurred in the base station indicated by the information received by the receiving unit.