Machine Diagnostic Device and Machine Diagnostic Method

The purpose of the present invention is to provide a machine diagnostic device that assists with sensor attachment such that malfunction sensing performance may be maintained even after maintenance of a device. The machine diagnostic device includes a sensor data acquisition part that acquires time-series sensor data that are measured by sensors that are attached to a machine that has one or more operating modes; a learning unit that statistically processes the sensor data prior to detachment of the sensors and computes a normal operation model; a malfunction diagnostic unit that diagnoses a malfunction of the machine on the basis of the sensor data and the normal operation model; and a sensor adjustment unit that, when the sensors are re-attached to the machine after the sensors have been detached therefrom, displays, in a display unit, as a sensor adjustment mode, discrepancies between the normal operation model prior to the detachment of the sensors and the post sensor attachment sensor data.