Electric power steering device and sensor abnormality detection device

An electric power steering device comprising:

• a steering force assist device that applies an assist force to a steering system by using a motor as a drive source;
• a rotation body that constitutes a part of the motor or the steering system and rotates as the motor rotates;
• a rotation sensor that outputs a sensor signal based on the rotation of the rotation body;
• a control means that controls operation of the steering force assist device to generate the assist force based on the sensor signal;
• and
• an abnormality detecting means that detects an abnormality in the sensor signal, wherein
• the control means controls the operation of the steering force assist device to apply instantaneous motor torque to the steering system, and
• the abnormality detecting means detects an abnormality in the sensor signal if the application of instantaneous motor torque is not reflected in the sensor signal.