An IP address distribution system comprising: a plurality of devices connected to a communication network established in a train; and an IP address distribution device to select, in response to a request from a device, a fixed IP address to be assigned to a requesting device and to transmit the IP address to the requesting device, the IP address distribution device being connected to the communication network, wherein the IP address distribution device includes: a display; an input unit operable by a user; a storage to store an IP address management table in which an IP address and an in-train installation position of a device in which the IP address needs to be used are managed in one-to-one correspondence with each other and which includes information as to whether the IP address is in use or not in use, an unset IP address associated with an in-train installation position of a device to which an IP address is to be set being registered in the IP address management table in advance; and an IP address distribution unit to refer to the IP address management table in response to receiving a request for an IP address from the requesting device, display, on the display, unused IP addresses in one-to-one correspondence with the in-train installation positions, accept, from the input unit, input information that is input by a user operating the input unit and is used for selecting, from among the unused IP addresses displayed on the display, an IP address corresponding to an in-train installation position of the requesting device, and select, from the IP address management table, a fixed IP address to be assigned to the requesting device on a basis of the input information. a plurality of devices connected to a communication network established in a train; and an IP address distribution device to select, in response to a request from a device, a fixed IP address to be assigned to a requesting device and to transmit the IP address to the requesting device, the IP address distribution device being connected to the communication network, wherein the IP address distribution device includes: a display; an input unit operable by a user; a storage to store an IP address management table in which an IP address and an in-train installation position of a device in which the IP address needs to be used are managed in one-to-one correspondence with each other and which includes information as to whether the IP address is in use or not in use, an unset IP address associated with an in-train installation position of a device to which an IP address is to be set being registered in the IP address management table in advance; and an IP address distribution unit to refer to the IP address management table in response to receiving a request for an IP address from the requesting device, display, on the display, unused IP addresses in one-to-one correspondence with the in-train installation positions, accept, from the input unit, input information that is input by a user operating the input unit and is used for selecting, from among the unused IP addresses displayed on the display, an IP address corresponding to an in-train installation position of the requesting device, and select, from the IP address management table, a fixed IP address to be assigned to the requesting device on a basis of the input information. a display; an input unit operable by a user; a storage to store an IP address management table in which an IP address and an in-train installation position of a device in which the IP address needs to be used are managed in one-to-one correspondence with each other and which includes information as to whether the IP address is in use or not in use, an unset IP address associated with an in-train installation position of a device to which an IP address is to be set being registered in the IP address management table in advance; and an IP address distribution unit to refer to the IP address management table in response to receiving a request for an IP address from the requesting device, display, on the display, unused IP addresses in one-to-one correspondence with the in-train installation positions, accept, from the input unit, input information that is input by a user operating the input unit and is used for selecting, from among the unused IP addresses displayed on the display, an IP address corresponding to an in-train installation position of the requesting device, and select, from the IP address management table, a fixed IP address to be assigned to the requesting device on a basis of the input information.