PROBLEM TO BE SOLVED: To provide a temperature-sensitive magnetic substance tag capable of easily and precisely detecting the temperature history of an object to be measured and to provide an apparatus for reading the same and a temperature history sensing system.;SOLUTION: The temperature-sensitive magnetic substance tag is previously constituted of a combination of magnetic substances in such a way as to emit higher harmonic waves or acoustic waves at the irradiation with an AC magnetic field or a pulse magnetic field in the case that it has exceeded a prescribed temperature. Such a magnetic substance tag is mounted to the object to be measured. An electromagnetic field is irradiated by an electromagnetic field irradiation means when measurement is required, and the higher harmonic waves or acoustic waves are converted into electric signals by an electromagnetic field sensing means or an acoustic wave sensing means. A signal processing means processes the acquired electric signals and determines whether the temperature-sensitive magnetic substance tag, in other words, the object to be measured has exceeded the prescribed temperature or not.;COPYRIGHT: (C)2005,JPO&NCIPI
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