Monitoring device and monitoring method

A monitoring device comprising:

• an individual alarm reception unit, including one or more processors, configured to receive individual alarms issued from a plurality of devices constituting an optical transmission network;
• a table in which a search operator for searching for necessary information required for treating the individual alarms in a same manner when specifications of the individual alarms are different from each other, is associated with information included in the individual alarms;
• a search operator extraction unit, including one or more processors, configured to extract the search operator using the information included in each of the individual alarms as a key;
• a rule in which the search operator is associated with the necessary information;
• and
• a unified alarm information generation unit, including one or more processors, configured to search the rule using the search operator as a key, compare the information included in the individual alarms with the necessary information described in the searched rule, and add information, that is included in the necessary information but not included in the individual alarms, to the individual alarms to generate unified alarm information.