A firmware update apparatus which communicates with a plurality of audio processing devices (1502-1510, 1602-1606), each audio processing device (1502-1510, 1602-1606) belonging to one of a plurality of device groups (1500, 1600), and which updates a firmware stored in each of the audio processing devices (1502-1510, 1602-1606), the firmware being a control program for controlling the audio processing device (1502-1510, 1602-1606), each of the audio processing devices (1502-1510, 1602-1606) including a first network interface for communicating with another audio processing device (1502-1510, 1602-1606) within a device group (1500, 1600) to which the audio processing device (1502-1510, 1602-1606) belongs, each of the audio processing devices (1502-1510, 1602-1606) transmitting or receiving an audio signal to or from another audio processing device (1502-1510, 1602-1606) within the device group (1500, 1600) through the first network interface, at least one audio processing device of each of the device groups (1500, 1600) including a second network interface for communicating with an audio processing device (1502-1510, 1602-1606) belonging to another device group (1500, 1600), the at least one audio processing device transmitting or receiving an audio signal to or from an audio processing device (1502-1510, 1602-1606) belonging to another device group (1500, 1600) through the second network interface to perform audio signal communication between the plurality of device groups (1500, 1600), the firmware update apparatus comprising: a device group specification part that specifies a device group (1500, 1600), whose firmware is to be updated, as an update target device group from among the plurality of device groups (1500, 1600) based on a manipulation by a user; and an update target device selection part that selects one or more of audio processing devices (1502-1510, 1602-1606) belonging to the update target device group as one or more of update target devices based on a manipulation by the user; characterized in that said firmware update apparatus further comprises an inter-group interface update specification part that specifies whether or not to update a firmware associated with the second network interface based on a manipulation by the user; and a firmware update instruction part (SP32, SP34) that transmits the update command instructing update of firmwares of the update target devices, including the firmware associated with the second network interface, to each of the update target devices, provided that information indicating update of the firmware associated with the second network interface has been set by the inter-group interface update specification part, and transmits the update command instructing update of firmwares of the update target devices, excluding the firmware associated with the second network interface, to each of the update target devices, provided that information indicating update of the firmware associated with the second network interface has not been set by the inter-group interface update specification part. a device group specification part that specifies a device group (1500, 1600), whose firmware is to be updated, as an update target device group from among the plurality of device groups (1500, 1600) based on a manipulation by a user; and an update target device selection part that selects one or more of audio processing devices (1502-1510, 1602-1606) belonging to the update target device group as one or more of update target devices based on a manipulation by the user; characterized in that said firmware update apparatus further comprises an inter-group interface update specification part that specifies whether or not to update a firmware associated with the second network interface based on a manipulation by the user; and a firmware update instruction part (SP32, SP34) that transmits the update command instructing update of firmwares of the update target devices, including the firmware associated with the second network interface, to each of the update target devices, provided that information indicating update of the firmware associated with the second network interface has been set by the inter-group interface update specification part, and transmits the update command instructing update of firmwares of the update target devices, excluding the firmware associated with the second network interface, to each of the update target devices, provided that information indicating update of the firmware associated with the second network interface has not been set by the inter-group interface update specification part.