A network managing device configured to manage a network in which a plurality of first stage switches having a plurality of nodes connected thereto respectively, a plurality of second stage switches to be upper switches of the first stage switches and a plurality of third stage switches to be upper switches of the second stage switches are connected in a configuration of Fat Tree and on which an all-to-all communication using a shift communication pattern is performed, the network managing device comprising: A) an initial address allocating unit configured to allocate an address to each of the nodes connected to the respective first stage switches by allocating a number to each of the nodes which is a serial address, is possessed serially by the nodes connected to the first stage switch, and is reduced in descending order of the number of the first stage switch; B) a connecting state acquiring unit configured to acquire each of connecting states from the first stage switches, the second stage switches and the third stage switches, the connecting states being a state of disposed cabling between the first stage switches, the second stage switches and the third stage switches; C) an erroneous connection detecting unit configured to compare the connecting state acquired by the connecting state acquiring unit with a prestored connecting state, thereby detecting an erroneous connection; and D) an address changing unit configured to change, based on the connecting state, the address of the node which is allocated by the initial address allocating unit to satisfy a first condition, when the erroneous connection is detected by the erroneous connection detecting unit, the first condition being satisfied when remainders obtained as a result of respective divisions which are acquired by dividing a transmitting destination number of a plurality of signals which the first stage switches receive from the connected node by a predetermined value are different from each other, the predetermined value being a half of a number of paths connecting to the first stage switch. A) an initial address allocating unit configured to allocate an address to each of the nodes connected to the respective first stage switches by allocating a number to each of the nodes which is a serial address, is possessed serially by the nodes connected to the first stage switch, and is reduced in descending order of the number of the first stage switch; B) a connecting state acquiring unit configured to acquire each of connecting states from the first stage switches, the second stage switches and the third stage switches, the connecting states being a state of disposed cabling between the first stage switches, the second stage switches and the third stage switches; C) an erroneous connection detecting unit configured to compare the connecting state acquired by the connecting state acquiring unit with a prestored connecting state, thereby detecting an erroneous connection; and D) an address changing unit configured to change, based on the connecting state, the address of the node which is allocated by the initial address allocating unit to satisfy a first condition, when the erroneous connection is detected by the erroneous connection detecting unit, the first condition being satisfied when remainders obtained as a result of respective divisions which are acquired by dividing a transmitting destination number of a plurality of signals which the first stage switches receive from the connected node by a predetermined value are different from each other, the predetermined value being a half of a number of paths connecting to the first stage switch.