The present invention provides an oral sensor device comprising: a sensor assembly which is bendable and generates an electrical signal by detecting an X-ray; and a window cover comprising a base portion and a side wall, the base portion being positioned on the front of a sensor panel with respect to the traveling direction of the X-ray, and covering the sensor panel, and the side wall protruding toward the rear from the lateral side of the edge of the base portion so as to cover the lateral surface of the sensor panel, and having a plurality of grooves formed on at least a part thereof.