1. A program structuring device comprising: a play-list collecting unit that collects a play list for a content in which a time series is defined; a first storage unit that stores cutoff points that appear in the play list and are breakpoints of a program structure of the content, in correspondence with a frequency of appearance of each of the cutoff points; a calculating unit that calculates a level of relevance between scene segments defined by the cutoff points from the frequency of appearance of each of the cutoff points; an extracting unit that extracts multi-level chapter divisions based on the level of relevance; and a second storage unit that stores the extracted multi-level chapter divisions structured into a tree form.