MEMS device with failure diagnosis function

A microelectromechanical systems device comprising:

• a substrate;
• a moving part, a fixed part, and an actuator that displaces said moving part, all of which being formed on said substrate;
• a control unit which drives said actuator to switch the position of moving part between binary states;
• vibration detecting means for detecting a micro vibration excited in said moving part in one of said binary switching states;
• a dynamic-characteristic analyzing means for analyzing a dynamic-characteristic of said moving part on the basis of an output from said vibration detecting means;
• a memory which stores data outputted from said dynamic-characteristic analyzing means;
• an operation unit which retrieves data from said memory, compares two temporally successive pieces of data, and calculates difference information between said two pieces of data;
• and
• a failure diagnosis unit which performs a failure diagnosis based on said difference information outputted from said operation unit.