Sensor device and article display shelf

A sensor device comprising:

• a sensor unit that emits light and receives light reflected by an object;
• and
• a reflection mirror unit that reflects light emitted from the sensor unit toward the object and reflects light reflected from the object toward the sensor unit,
• wherein the reflection mirror unit includes a plurality of reflection mirrors each configured to reflect light emitted from the sensor unit and light reflected from the object on a same reflection surface, and
• wherein each of the plurality of reflection mirrors includes, on the same reflection surface, a first part and a second part having lower reflectance than the first part, the second part being arranged such that the second part surrounds the first part.