A body of a thermometer (1001), a first location to be measured (1002), a second location to be measured (1003) and a third installation location (1004) is established by the thermometer management system. Further, communication lines (1005) are connected to network units at each location to be measured. Network units relay the sensor output from a sensor part to the communication lines. A sensor part is fixed to an object to be measured and sends a sensor output in response to the temperature of the object to be measured. A network unit has a radio frequency identifier (RFID) reader and transmits to the thermometer body commands and the like stored in the memory of an RFID card in response to approach of the RFID card arranged corresponding to a location to be measured. The thermometer body receives the commands and the like and performs predetermined operations.