PURPOSE: To obtain a satisfactory visual field regardless of a surrounding environment by providing a cover glass equipped with a dew drop sensor and a heater in front of a case which houses a monitor camera.

CONSTITUTION: The camera main body is housed in a case 5, and an aperture for receiving a video is provided in the front wall of the case 5, and covered with a cover glass 6 which protects the camera main body from the outside environment. The surface of the cover glass 6 is equipped with a heater function in which an electrically conductive film 7 having translucency is formed by vapor deposition, and a dew drop sensor 17 is formed integrally with the conductive film 7. That is, the dew drop and a freezing state generated at the cover glass 6 are sensed by the dew drop sensor 17 provided on the glass surface, and the energization of the heater of the conductive film 17 formed on the glass surface is controlled by the detection signal of the dew drop sensor 17. Therefore, heating suitable to the situation of the glass surface can be attained, and the satisfactory visual field can be obtained regardless of the surrounding temperature environment.