As a music equipment is connected to a music processing apparatus, necessary communication ports corresponding to the connected music equipment are automatically set in the processing apparatus. The thus-set communication ports are each assigned the name of the corresponding equipment so that the equipment and the communication ports can be associated with each other. Once the equipment is disconnected from the apparatus, the disconnected equipment is converted into a dummy state and displayed in a predetermined dummy display style. When a project file has been read which includes track data, identification information of a currently-set external equipment and parameters of the external equipment, the detected external equipment is associated with any one of external equipments which had been set for use at the time of storage of the project file. By transferring parameters, stored in a memory, to the external equipment that could be associated, parameter synchronization can be effected.