PURPOSE: To provide a soundness evaluating device for a motor-driven valve which is applicable to a nuclear plant effectively, which enables simple evaluation of the soundness by means of remote control, etc., and which allows easy installation works, etc., in a place apart from the motor driven valve.

CONSTITUTION: A current sensing part 16 is furnished to sense the current for driving a motor 3. An A/D convertor 18 is provided to convert the sensing signal given by this current sensing part 16 into digital signals. A frequency analyzer 19 is furnished to extract the revolving speed component of valve stem by frequency analyzing the signal value emitted by the A/D convertor 18. An calculative operational part 20 is provided which previously retain as data the relationship between the valve stem revolving speed and thrust load and which evaluates thsoundness of the valve stem by calculating the thrust load thereon from the revolving speed component obtained by the frequency analyzer on the basis of this data.