A tag identification device automatically identifies a correspondence relationship between a tag name arbitrarily set by a user and a process value. The tag identification device includes a processor, in a first process, that obtains first definition information in which the tag name, a type of tag data which is handled using the tag name, an upper limit value, an lower limit value, and an engineering unit are defined for each tag. The processor extracts, from the first definition information, a tag coinciding with at least one of the type of tag, the upper limit value, the lower limit value, and the engineering unit of a predetermined first process value. The processor selects the tag data handled using the tag name defined for the extracted tag, using an actual measurement value of the tag data. The processor identifies the selected tag data as the first process value.