A network management apparatus for managing a plurality of managed apparatuses in a photographing network, wherein the network management apparatus operates as one of: a master apparatus (101, 202) that transmits a control command to control a photographic operation; and a slave apparatus (204, 205) that receives a photographic operation control command, and wherein the network management apparatus is adapted to maintain operation mode information in a device information list indicating whether each of the plurality of managed apparatuses operates as one of: a master apparatus (101, 202) that transmits a control command to control a photographic operation; and a slave apparatus (204, 205) that receives a photographic operation control command, and the network management apparatus comprises: determination means for selecting, from the plurality of managed apparatuses, a candidate apparatus that becomes a new network management apparatus in a case that the network management apparatus is disconnected from the network, said determination means being configured to use the operation mode information to select a master apparatus as the candidate apparatus in preference to a slave apparatus when selecting from the plurality of apparatuses and to correspondingly update said network device information list; and transmission means (102, 103, S609) for transmitting, at least to the managed apparatus selected as the candidate apparatus by said determination means, an updated network device information list indicating the operation mode of each apparatus in the network and further indicating that the selected managed apparatus is selected as the candidate apparatus. a master apparatus (101, 202) that transmits a control command to control a photographic operation; and a slave apparatus (204, 205) that receives a photographic operation control command, and wherein the network management apparatus is adapted to maintain operation mode information in a device information list indicating whether each of the plurality of managed apparatuses operates as one of: a master apparatus (101, 202) that transmits a control command to control a photographic operation; and a slave apparatus (204, 205) that receives a photographic operation control command, and the network management apparatus comprises: determination means for selecting, from the plurality of managed apparatuses, a candidate apparatus that becomes a new network management apparatus in a case that the network management apparatus is disconnected from the network, said determination means being configured to use the operation mode information to select a master apparatus as the candidate apparatus in preference to a slave apparatus when selecting from the plurality of apparatuses and to correspondingly update said network device information list; and transmission means (102, 103, S609) for transmitting, at least to the managed apparatus selected as the candidate apparatus by said determination means, an updated network device information list indicating the operation mode of each apparatus in the network and further indicating that the selected managed apparatus is selected as the candidate apparatus. a master apparatus (101, 202) that transmits a control command to control a photographic operation; and a slave apparatus (204, 205) that receives a photographic operation control command, and the network management apparatus comprises: determination means for selecting, from the plurality of managed apparatuses, a candidate apparatus that becomes a new network management apparatus in a case that the network management apparatus is disconnected from the network, said determination means being configured to use the operation mode information to select a master apparatus as the candidate apparatus in preference to a slave apparatus when selecting from the plurality of apparatuses and to correspondingly update said network device information list; and transmission means (102, 103, S609) for transmitting, at least to the managed apparatus selected as the candidate apparatus by said determination means, an updated network device information list indicating the operation mode of each apparatus in the network and further indicating that the selected managed apparatus is selected as the candidate apparatus. determination means for selecting, from the plurality of managed apparatuses, a candidate apparatus that becomes a new network management apparatus in a case that the network management apparatus is disconnected from the network, said determination means being configured to use the operation mode information to select a master apparatus as the candidate apparatus in preference to a slave apparatus when selecting from the plurality of apparatuses and to correspondingly update said network device information list; and transmission means (102, 103, S609) for transmitting, at least to the managed apparatus selected as the candidate apparatus by said determination means, an updated network device information list indicating the operation mode of each apparatus in the network and further indicating that the selected managed apparatus is selected as the candidate apparatus.