According to the present invention, the work status at an actual site is represented using a combination of component statuses. A degree of damage that takes into account the manner of use at the actual site is predicted by associating test data collected in a component status test. The objective of the present invention is to estimate, with high accuracy, the degree of damage to a device operating in an actual environment. In order to achieve this objective, this damage estimation device is provided with: a component status classification processing unit that classifies the operating status of a device; a component status characteristic amount storage unit that stores a characteristic amount for classification processing by the component status classification processing unit; and a damage degree storage unit for each component status, said damage degree storage unit storing the degree of damage to various regions of a device for each component status, wherein the degree of damage is measured in advance for each component status or is calculated using a simulation. The damage estimation device is characterized by collecting sensor/control data required for device status classification, classifying component status using the component status classification processing unit, calculating the classified result and the degree of damage corresponding to said result using the damage degree storage unit for each component status, and outputting the degree of damage.