MONITORING DEVICE, MONITORING METHOD, AND MONITORING SYSTEM

A monitoring device includes: an instruction unit configured to instruct a vehicle to acquire appearance data of a monitoring object designated by a user; a detection unit configured to receive the appearance data from the vehicle and to detect whether a state of the monitoring object has changed based on the appearance data; and a monitoring result notifying unit configured to notify the user of a monitoring result of the monitoring object when the detection unit detects that the state of the monitoring object has changed.