An attribute value of a matter accompanied by a sensor is transmissibly accessible in a sensor node system constituted by wireless terminal computers having the sensor, the wireless communication base stations and server computers. The wireless terminal computer reports at the time of wireless communication an identification number of a wireless communication base station with which it communicates previously. A relay processing service is dynamically constituted so that when a wireless communication base station different from itself is reported, the wireless base station as the communication counter-part can transmissbly look up the wireless terminal computer from a host computer.