To reduce differences in the number of times of operating an input device up to the search of an objective data at the time of collectively displaying data in each tag.

When a display mode uses a variable tag, data are read out, the read data are rearranged in the order of the Japanese syllabary and the total number of data is counted (step S22). New headings are prepared from the total number of data so that the volume of tag data included in each tag is almost equal and data are allocated to respective headings (step S23). Then tag data included in a selected tag are displayed (step S25).