A control program delivery system comprising: a control device (13, 23) including non-rewritable first storage means for storing first authentication information which is encrypted, and rewritable second storage means; a repeater device to which second authentication information is assigned; and a server for delivering a control program, wherein the repeater device includes request means for making a request for transmission of the first authentication information to the control device; first transmission means for transmitting the first authentication information which is received from the control device and its own second authentication information to the server; and second transmission means for transmitting the control program to the control device (13, 23), in a case of receiving the control program from the server, wherein the server includes reception means for receiving the first authentication information and the second authentication information from the repeater device; authentication means for verifying whether or not the control device and the repeater device have legitimate authorities by decoding the first authentication information and the second authentication information to determine whether or not the first authentication information and the second authentication information is present in a list owned by the server; and transmission means for transmitting the control program, which is generated by the server not to be executed if the first authentication information is not verified by the control device, to the repeater device, in a case where the control device and the repeater device have legitimate authorities, wherein the control device (13, 23) includes write means for writing the control program into the second storage means, in a case of receiving the control program from the repeater device, and wherein the control program is configured to verify the first authentication information stored in the first storage means, when execution of the program is started, and to permit the program to be continuously executed, only in a case where the first authentication information is verified. a control device (13, 23) including non-rewritable first storage means for storing first authentication information which is encrypted, and rewritable second storage means; a repeater device to which second authentication information is assigned; and a server for delivering a control program, wherein the repeater device includes request means for making a request for transmission of the first authentication information to the control device; first transmission means for transmitting the first authentication information which is received from the control device and its own second authentication information to the server; and second transmission means for transmitting the control program to the control device (13, 23), in a case of receiving the control program from the server, request means for making a request for transmission of the first authentication information to the control device; first transmission means for transmitting the first authentication information which is received from the control device and its own second authentication information to the server; and second transmission means for transmitting the control program to the control device (13, 23), in a case of receiving the control program from the server, wherein the server includes reception means for receiving the first authentication information and the second authentication information from the repeater device; authentication means for verifying whether or not the control device and the repeater device have legitimate authorities by decoding the first authentication information and the second authentication information to determine whether or not the first authentication information and the second authentication information is present in a list owned by the server; and transmission means for transmitting the control program, which is generated by the server not to be executed if the first authentication information is not verified by the control device, to the repeater device, in a case where the control device and the repeater device have legitimate authorities, reception means for receiving the first authentication information and the second authentication information from the repeater device; authentication means for verifying whether or not the control device and the repeater device have legitimate authorities by decoding the first authentication information and the second authentication information to determine whether or not the first authentication information and the second authentication information is present in a list owned by the server; and transmission means for transmitting the control program, which is generated by the server not to be executed if the first authentication information is not verified by the control device, to the repeater device, in a case where the control device and the repeater device have legitimate authorities, wherein the control device (13, 23) includes write means for writing the control program into the second storage means, in a case of receiving the control program from the repeater device, and wherein the control program is configured to verify the first authentication information stored in the first storage means, when execution of the program is started, and to permit the program to be continuously executed, only in a case where the first authentication information is verified.