Abnormality diagnosis device and program capable of accurately determining a state of a device to be diagnosed

The subject of the present invention is to provide an abnormality diagnosis device capable of accurately determining a state of a device to be diagnosed. The abnormality diagnosis device 100 comprises a failure mode selection part 106 for selecting the failure mode to be the detected target; a teaching data forming part 103 for generating teaching data DT for determining whether the diagnosed target device 10 suffers from a failure based on the data corresponding to the failure mode in the diagnosed target device 10 or other devices, wherein the data is the failure corresponding measurement data; a measurement item importance calculation part 104 for calculating the importance of the measurement item in the failure mode based on the teaching data DT; a feature quantity selection part 105 for selecting a part of the measurement items as the feature quantity for the failure mode based on the calculated importance; an abnormality calculation part 107 for calculating the abnormality degree A corresponding to the