Reader, a computer program and reading system

A tag reader/writer repeatedly reads data from each responding IC-tag existing in an area where communication with the reader/writer can be established in a noncontact way. The reader/writer transmits the read data to an administrative device. The administrative device generates data which shows the result of reading in chronologic order determines the maximum number of continuous successful read operations for each tag and the ratio of this maximum number and the number of read instructions. On the basis of this ratio it is decided whether the read data originates from a desired tag response or from an accidental response of a nearby tag that should not be read.