Abstract. We propose the sensor network system using the microcomputer board that can connect to the Internet. This proposed system can acquire information from the sensor of the microcomputer group arranged on the network, and can view collected information on Web browser. In this paper, it is shown to be able to construct easily the microcomputer's sensor network which is combined microcomputer modules (Micro Cube) and the database server and the Web application server. The system that measured the room temperature in school campus was constructed, it has run for four months, and the effectiveness is verified.