Abstract: An inspecting apparatus includes a measuring device and a processing unit. The measuring device is provided with a vibration detector for detecting the vibration of a steam trap when a valve thereof is closed. The processing unit is provided with a performance deterioration value calculator for converting the detected vibration level of the steam trap into a sealing performance deterioration value representing a deterioration level of the sealing performance of the valve of the steam trap under a reference steam pressure value using a working steam pressure value, a display for displaying a rank of the sealing performance obtained based on the sealing performance deterioration value, and a trap list storage for storing the sealing performance deterioration value and the rank of the sealing performance as well as ID information of the steam trap. The steam trap can be more precisely inspected.