A network apparatus, in which n 3 signal transmitting/receiving devices have n 3 addresses of serial numbers, n is a natural number equal to or greater than 2, the network apparatus comprising: n 2 first signal transmitting units (B1 to B9) configured to be connected in one-to-one correspondence with n 2 combinations of signal transmitting/receiving devices classified to have n sequential addresses from the minimum address and receive n signals, which are different in terms of the remainder of a destination address divided by n, from the signal transmitting/receiving device and transmit the received signals to n different destinations; n 2 second signal transmitting units (M1 to M9) configured to receive n signals, which are equal in terms of the remainder of a destination address divided by n, from the different first signal transmitting units (B1 to B9) and transmit the received signals to a destination corresponding to the remainder of a destination address of each of the received signals divided by n 2; and n 2 third signal transmitting units (T1 to T9) configured to have a Fat Tree configuration with respect to the second signal transmitting unit (M1 to M9), receive n signals, which are equal in terms of the remainder of a destination address divided by n 2, from n different second signal transmitting units (M1 to M9), and output the received signal, which is received from the second signal transmitting unit (M1 to M9), to the second signal transmitting unit (M1 to M9) connected to the first signal transmitting unit (B1 to B9) connected to the signal transmitting/receiving device having a destination address of the received signal; wherein the first signal transmitting units (B1 to B9) are classified into first groups each including n units based on the addresses of the connected signal transmitting/receiving device, the second signal transmitting units (M1 to M9) are classified into second groups each including n units, the first signal transmitting units (B1 to B9) are sequentially numbered, and the first signal transmitting units (B1 to B9) are connected to the second signal transmitting units (M1 to M9) constituting the Fat Tree together with the third signal transmitting units (T1 to T9) so as to interchange a connection point of one or more second signal transmitting units (M1 to M9) and a connection point of another one of or more second signal transmitting units (M1 to M9) in a Fat Tree configuration between the first signal transmitting units (B1 to B9) and the second signal transmitting units (M1 to M9), by selecting the first signal transmitting units (B1 to B9) connecting to the second signal transmitting units (M1 to M9) in each of second groups among each of first groups based on the number of the first signal transmitting units (B1 to B9). n 2 first signal transmitting units (B1 to B9) configured to be connected in one-to-one correspondence with n 2 combinations of signal transmitting/receiving devices classified to have n sequential addresses from the minimum address and receive n signals, which are different in terms of the remainder of a destination address divided by n, from the signal transmitting/receiving device and transmit the received signals to n different destinations; n 2 second signal transmitting units (M1 to M9) configured to receive n signals, which are equal in terms of the remainder of a destination address divided by n, from the different first signal transmitting units (B1 to B9) and transmit the received signals to a destination corresponding to the remainder of a destination address of each of the received signals divided by n 2; and n 2 third signal transmitting units (T1 to T9) configured to have a Fat Tree configuration with respect to the second signal transmitting unit (M1 to M9), receive n signals, which are equal in terms of the remainder of a destination address divided by n 2, from n different second signal transmitting units (M1 to M9), and output the received signal, which is received from the second signal transmitting unit (M1 to M9), to the second signal transmitting unit (M1 to M9) connected to the first signal transmitting unit (B1 to B9) connected to the signal transmitting/receiving device having a destination address of the received signal; wherein the first signal transmitting units (B1 to B9) are classified into first groups each including n units based on the addresses of the connected signal transmitting/receiving device, the second signal transmitting units (M1 to M9) are classified into second groups each including n units, the first signal transmitting units (B1 to B9) are sequentially numbered, and the first signal transmitting units (B1 to B9) are connected to the second signal transmitting units (M1 to M9) constituting the Fat Tree together with the third signal transmitting units (T1 to T9) so as to interchange a connection point of one or more second signal transmitting units (M1 to M9) and a connection point of another one of or more second signal transmitting units (M1 to M9) in a Fat Tree configuration between the first signal transmitting units (B1 to B9) and the second signal transmitting units (M1 to M9), by selecting the first signal transmitting units (B1 to B9) connecting to the second signal transmitting units (M1 to M9) in each of second groups among each of first groups based on the number of the first signal transmitting units (B1 to B9).