The utility model discloses a cable pit detection instrument, this cable pit detection instrument includes: take the LED light source the camera, be used for controlling the controller of camera and LED light source and the display terminal who is connected with controller signal, the camera is connected through the signal line that has the bellows with the controller, still establishes the pipe outside signal connection line including the cover, the pipe has the camera protection portion in the jack -up hole that can stretch into cable trench cover. According to the utility model discloses a cable pit detection instrument through providing the pipe that can stretch into the jack -up hole, has avoided the problem that the camera harmd with the pore wall contact in jack -up hole. But and through the crooked shape in the pipe control signal line entering cable pit, prevent that the camera from touching the support in the cable pit and damaging.