An authorization system comprising: a client device; a local authentication server connected to the client device via a local network; and an authorization server configured to issue an access token based on an authorization operation performed by a user, characterized in that the client device comprises registering means configured to register a first authorization token which is issued by the authorization server based on an authorization operation performed by the user, as representative authorization token information; authorization request means configured to transmit local user information of the user to the local authentication server and to transmit the representative authorization token information with an authorization token generation request, in response to receiving a result of correct local authentication performed by the local authentication server to the authorization server; wherein the authorization server comprises receiving means configured to receive the authorization token generation request along with the representative authorization token information and the local user information from the client device; authorization processing means configured, in a case where the client device is authenticated successfully on the basis of the representative authorization token information received along with the authorization token generation request, to respond with a second authorization token to the client device and generating and storing authorization token information by associating the local user information received along with the authorization token generation request with the second authorization token; and responding means configured to receive an authorization token verification request including the second authorization token from an application server that has received a processing request along with the second authorization token from the client device, and, in the case that the authorization token is verified successfully on the basis of the received second authorization token and the authorization token information, responding with the local user information included in the authorization token information to the application server. a client device; a local authentication server connected to the client device via a local network; and an authorization server configured to issue an access token based on an authorization operation performed by a user, characterized in that the client device comprises registering means configured to register a first authorization token which is issued by the authorization server based on an authorization operation performed by the user, as representative authorization token information; authorization request means configured to transmit local user information of the user to the local authentication server and to transmit the representative authorization token information with an authorization token generation request, in response to receiving a result of correct local authentication performed by the local authentication server to the authorization server; wherein the authorization server comprises receiving means configured to receive the authorization token generation request along with the representative authorization token information and the local user information from the client device; authorization processing means configured, in a case where the client device is authenticated successfully on the basis of the representative authorization token information received along with the authorization token generation request, to respond with a second authorization token to the client device and generating and storing authorization token information by associating the local user information received along with the authorization token generation request with the second authorization token; and responding means configured to receive an authorization token verification request including the second authorization token from an application server that has received a processing request along with the second authorization token from the client device, and, in the case that the authorization token is verified successfully on the basis of the received second authorization token and the authorization token information, responding with the local user information included in the authorization token information to the application server.