To provide a wireless IC tag for monitoring the temperature, hydrogen-ion exponent and strain of a concrete structure.

In a wireless IC tag 1 which is attached to or embedded in a concrete structure 11, ferroelectric memory, which uses a ferroelectric having a power supply section which receives radio waves from the outside and generates a current by resonating with the radio waves and an antenna section which performs wireless communication in a prescribed frequency band, a temperature sensor 4, a Ph sensor 5 and a strain sensor 6 are mounted on a substrate 2. At least one kind of data selected from among the temperature data of the structure measured by means of the temperature sensor 2, the hydrogen-ion exponent data of the structure measured by means of the Ph sensor 5, and the strain data of the structure measured by means of the strain sensor 6 is stored in the ferroelectric memory.