A music processing apparatus capable of performing music processing, said music processing apparatus being capable of registering plug-in software (12, 16), having a predetermined music processing function, into a rack object to thereby use the music processing function of the plug-in software in part of the music processing, said music processing apparatus comprising: a first interface section (8; 25) that connects said music processing apparatus to a music network capable of real-time transmission of the performance events and/or audio signals; a storage section (3A, 3B, 4; 43) for storing, for each equipment (31 - 34) registered for use in said music processing apparatus, equipment data including a name of the equipment and information of a connection port to be used for connecting the equipment (31 - 34) to the music processing of said music processing apparatus; a library section (3A, 3B, 4; 43) capable of storing a plurality of sets of the equipment data; characterized in that said music processing apparatus further comprises: a connection detection section for detecting an external equipment newly connected to the network and having a music processing function identical in type to the music processing function of the plug-in software and for generating equipment data of the detected external equipment on the basis of information acquired from the detected external equipment; an automatic registration section (S55, S58) for causing, when connection of a new external equipment is detected by said connection detection section and if the new external equipment has not yet been registered for use, equipment data of the new external equipment to be stored into said library section; a use-registration section (S40, S41, S42) for selecting, in response to operation by a user, any one of a plurality of equipments, having their respective equipment data stored in said library section, to register the selected equipment for use and writing the equipment data of the selected equipment into said storage section, and for deleting, when the selected equipment having been registered for use is the external equipment detected by said connection detection section, the equipment data of the external equipment from said library section; and a rack registration section (S81, S82, S85, S86) for registering, in response to operation by the user, the equipment, having been registered for use, into the rack object, wherein the music processing function of the equipment registered in the rack object is usable as part of the music processing in a substantially same manner as the music processing function of the plug-in software. a first interface section (8; 25) that connects said music processing apparatus to a music network capable of real-time transmission of the performance events and/or audio signals; a storage section (3A, 3B, 4; 43) for storing, for each equipment (31 - 34) registered for use in said music processing apparatus, equipment data including a name of the equipment and information of a connection port to be used for connecting the equipment (31 - 34) to the music processing of said music processing apparatus; a library section (3A, 3B, 4; 43) capable of storing a plurality of sets of the equipment data; a connection detection section for detecting an external equipment newly connected to the network and having a music processing function identical in type to the music processing function of the plug-in software and for generating equipment data of the detected external equipment on the basis of information acquired from the detected external equipment; an automatic registration section (S55, S58) for causing, when connection of a new external equipment is detected by said connection detection section and if the new external equipment has not yet been registered for use, equipment data of the new external equipment to be stored into said library section; a use-registration section (S40, S41, S42) for selecting, in response to operation by a user, any one of a plurality of equipments, having their respective equipment data stored in said library section, to register the selected equipment for use and writing the equipment data of the selected equipment into said storage section, and for deleting, when the selected equipment having been registered for use is the external equipment detected by said connection detection section, the equipment data of the external equipment from said library section; and a rack registration section (S81, S82, S85, S86) for registering, in response to operation by the user, the equipment, having been registered for use, into the rack object, wherein the music processing function of the equipment registered in the rack object is usable as part of the music processing in a substantially same manner as the music processing function of the plug-in software.