The invention discloses a novel automatic steel cord looseness detector. The detector comprises a motor reduction box and a bracket, and is characterized by further comprising a computer and a high-definition camera, wherein a front supporting seat is arranged at the head part of the bracket; a rear supporting seat is arranged at the tail part of the bracket; a steel cord sequentially passes through a first steel cord clamp, a pressing die, a second steel cord clamp, a steel cord pre-tension setting point and a sliding wheel from head to tail, and is downwards connected with a second hanging hammer; the high-definition camera is communicated with the computer, is arranged on the rear supporting seat, and directly faces to a looseness decision point. The detector disclosed by the invention has the advantages that the camera automatically shoots under the control of the computer, so that detection data are recorded and saved, and data information from a plurality of in-use looseness detectors are managed in a centralized manner through network interfaces, therefore the product quality situation in a production process is further conveniently managed and controlled by quality assurance personnel.