1. A digital content editing apparatus that edits a content having license information defining a grant for a reusing operation or a multiple content including a plurality of the contents, comprising: a reuse license processor that obtains a constraint indicative of a condition on reuse between the content or the multiple content and a content other than the content or the multiple content from the license information of the content or the multiple content; an instruction generator that generates an operation execution instruction of reusing the content or the multiple content according to the constraint obtained by the reuse license processor, a reusing unit that reuses the content or the multiple content based on the operation execution instruction generated by the instruction generator, and an editor that edits the content or the multiple content reused by the reusing unit.