A device retrieval system in a network system including a plurality of devices each having at least one attribute. The retrieval system includes: a plurality of device registration units, a device retrieval unit and an identity judgment unit. The device registration unit registers at least a part of the devices and attributes thereof while associating the devices with the attributes respectively. The device retrieval unit retrieves devices and attributes thereof from the devices and the attributes registered in the device registration units. The identity judgment unit judges identity as to whether a device retrieved from one of the device registration units is identical to a device retrieved from one of the others of the device registration units, based on common points of attributes of the retrieved devices.