Provided is a dialysis treatment instrument monitoring system capable of communicating with an extrahospital terminal via the Internet without affecting an intrahospital network. In the hospital equipped with a dialysis treatment instrument monitoring system monitoring dialysis treatment instruments including a dialysate feeding device, a bulk powder dissolving device, and a RO device, while a staff is absent in the hospital, the dialysate feeding device and the bulk powder dissolving device perform a dialysis preparation processing of cleaning and sterilizing inside the devices, and stop if an error occurs during execution of the dialysis preparation processing. If an error occurs in any of the dialysis treatment instruments, a network camera takes an image of a display of the dialysis treatment instrument in which the error occurred, and transmits image data to the terminal on the Internet via a mobile router dedicated to the dialysis treatment instrument monitoring system.