Provided is a power conversion device with which it is possible to acquire a sign of a system stop before the system stops, and to minimize the nonworking time of the system. A power conversion device for converting DC voltage or AC voltage into AC voltage, the power conversion device being characterized by having an abnormality detection unit for detecting abnormalities in the power conversion device, a restart unit for stopping the power conversion device and automatically performing a restart when the abnormality detection unit has detected an abnormality, a restart recording unit for recording restart information of when the restart unit has restarted, and a sign diagnostic unit for inputting the restart information recorded by the restart recording unit and performing a sign diagnosis of the abnormality in the power conversion device on the basis of the restart information, the sign diagnostic unit performing the sign diagnosis on the basis of the number of restarts and outputting a sign diagnostic result.