objects to be measured such as temperatures or a like further the power source managing section 302 has the transmitting unit 40 start so as to produce communication data as shown in fig2 by communication data producing section 401 and transmits communication data from the communication section 402 after transmitting communication data the power source managing section 302 stops supply of power to the data processing section 102 the control circuit 201 and the transmitting unit 40 by receiving transmit completion signal from the transmitting unit 40 that is the transmitting unit 40 is operated intermittently as shown in fig3 by operating the monitoring terminal device of the embodiment as above currents required except when data is transmitted is standby current of only the sensor 101 and therefore power consumption is greatly reduced the thermistor consumes power supply more or less because of being a resistance even during standby state but the bimetallic thermometer the lead switch and the mercury switch consume no power supply at all when they are used setting the state of switch off into standby state as a result power consumption during standby can be zero perfectly in the present invention since the transmitting unit 40 only when a change in the physical quantity measured by the sensor unit 10 as shown by the number.