In an insertion operation for combined use of contents in a content editing device such as a portable phone, if content without being combined is authorized content, all restriction conditions that have been added to content to be inserted and existing content are initially extracted. The restriction condition refers to information restricting combination with other content or information restricting combination with specific content. The content editing device investigates whether or not the restriction condition described above is satisfied with respect to all contents, and allows insertion of the content in the existing content only when the restriction condition is satisfied.