To provide a title assignment device capable of assigning different appropriate titles to a plurality of images.

This device comprises an image storage part storing a plurality of taken images; an imaging time storage part storing imaging times of the plurality of taken images; a period term storage part storing, in conformation to periods, a plurality of terms relevant to a plurality of periods differed in time width including the respective periods; a period term selection part selecting, in conformation to a period containing an imaging time, a term stored in the period term storage part; and a title assignment part assigning a title to a taken image by use of the selected term. When the title assignment part assigns the same title to a first taken image and a second taken image, the period term selection part selects, from the terms stored by the period term storage part in conformation to the imaging time of the first taken image, a first term related to a period with a time width shorter than the term previously assigned to the first taken image, and the title assignment part reassigns a title to the first taken image by use of this first term.