1. A firmware update apparatus which communicates with a plurality of audio processing devices, each audio processing device being classified as one of a plurality of device types and transmitting an audio signal over a network to other audio processing device or receiving an audio signal over a network from other audio processing device, and which updates a firmware stored in each of the audio processing devices, the firmware being a control program for controlling the audio processing device, the firmware update apparatus comprising: a reference device specification part that specifies one of the plurality of audio processing devices as a reference device based on a manipulation by a user; a version number acquisition part that acquires version numbers of firmwares stored in the respective audio processing devices from the audio processing devices; a matching table storage that stores a matching table defining a combination of compatible version numbers of firmwares from among combinations of version numbers of firmwares; an incompatible device display part that performs display for specifying an audio processing device that stores a firmware that does not satisfy compatibility defined in the matching table with a firmware stored in the reference device; an update target type selection part that specifies a firmware update target device type from among the plurality of device types based on a manipulation by the user; and a firmware update instruction part that transmits an update command instructing update of the firmware to one or more of audio processing devices belonging to the firmware update target device type selected by the update target type selection part.