A non-linear editing device capable of removing a medium from a system during editing or even after editing by copying a material file in the medium to another medium such as a built-in hard disk during editing and automatically changing a reference destination of material. This non-linear editing device includes a detachable first material storage part, a second material storage part, a material reference management part for managing a reference to the material file from a clip, and a material copying management part for allowing the material reference management part to execute the change of reference information.