To provide a contactless IC tag with a memory sensor and an environmental security method making manipulation of measurement results impossible or difficult physically and permitting reuse regardless of a code or keyword.

This IC tag with the memory sensor consists of the memory sensor 1, a control part 2, a memory 3, an antenna 4, a sensor reset means 10, a nonvolatile counter 11, and a fuse 12. A counter set signal output from the control part 2 to the nonvolatile counter 11 is output through an electric circuit equipped with the fuse 12 which connects the control part 2 and the counter 11 electrically, and a fuse disconnect signal is output to the fuse 12 from the control part 2. By this arrangement, after initializing the nonvolatile counter 11, a fuse disconnect signal is output to the fuse 12, and the connection between the control part 2 and the nonvolatile counters 11 is disconnected, thus making the operation of the nonvolatile counter 11 enabled.