The invention relates to a tool, specifically a tool for laying and fixing an optical fiber, and belongs to the technical field of optical fiber laying devices. The tool comprises a supporting roller,an optical fiber centering device, an adhesive coating device, an adhesive flattening device and a pedestal. The pedestal is sequentially provided with the supporting roller, the optical fiber centering device, the adhesive coating device and the adhesive flattening device. The supporting roller, the optical fiber centering device, the adhesive coating device and the adhesive flattening device are located on the same line. A front guide roller is disposed between the supporting roller and the optical fiber centering device, and a rear guide roller is disposed between the adhesive coating device and the adhesive flattening device. The tool achieves the automatic laying and fixing of the optical fiber in the production of a photoelectric composite conductor, reduces the manual operation, greatly improves the production efficiency, and enables the batch production of products to be possible.