A relay device includes an acquisition unit that acquires, upon detection of a change of settings concerning a network environment of an external system or the relay device, information related to the change; a generation unit that generates setting change information for causing settings of the external system to match settings of the relay device with reference to the information acquired by the acquisition unit; and an information setting unit that causes the setting change information generated by the generation unit to be set in the external system by transmitting the setting change information to the external system.