An information processing device that detects an anomaly in an in-vehicle network provided in a vehicle includes: a local rule storage in which at least an individual rule which is a rule generated for the vehicle is stored; a global rule storage in which an integrated rule which is a rule generated for a plurality of vehicles including the vehicle is stored; and a processing unit that performs, using a rule stored in at least one of the local rule storage or the global rule storage, an anomaly detection process on a frame transmitted on the in-vehicle network.