A music edit device realizing automatic DJ remix play under light load by using timeline metadata including the beat and the melody structure of a musical composition. The music edit device comprises a synchronous reproduction control unit which sends master beats to a remixing unit and reproduces musical compositions according to the remixing which the remixing unit instructs the synchronous reproduction control unit to perform according to a remix pattern and metadata, and a mixing section for mixing the reproduced musical compositions. The synchronous reproduction control unit has a phase comparator for comparing the phase of the beat sync signal created from the metadata supplied from the remixing unit with the phase of the master beat signal, an integrating section for integrating the phase comparison output from the phase comparator, and a correction section for correcting the tempo according to the integral output from the integrating section.