A remote operation system comprising: communication devices; an external device that specifies at least one communication device as a target for a remote operation among the communication devices, and accepts an input of a remote operation content to be executed for the specified communication device; and a relay device for relaying communication between the specified communication device and the external device, wherein the relay device comprises: storage means for storing the remote operation content accepted by the external device; and notification means for notifying the specified communication device of the remote operation content, wherein the relay device rejects storage of the operation content by the storage means or notification of the operation content by the notification means when the remote operation content accepted by the external device is an operation content that is not authorized by the external device, and wherein upon receiving, from a communication device, a notification indicating that an access authorization function is activated and informing that the communication device is in a state of being able to accept a remote operation, the notification means starts notification of the remote operation content for the communication device stored in the storage means, and wherein the communication devices further comprise: internal function processing means; and access management means for checking whether an access authorization function is activated, and accepting the notification of the remote operation content by the notification means to cause the internal function processing means to operate when the access authorization function is activated, and wherein when there is an interrupt operation for the communication device before completion of the operation of the internal function processing means according to the remote operation content for the communication device stored in the storage means, the access management means deactivates the access authorization function and executes the interrupt operation. communication devices; an external device that specifies at least one communication device as a target for a remote operation among the communication devices, and accepts an input of a remote operation content to be executed for the specified communication device; and a relay device for relaying communication between the specified communication device and the external device, wherein the relay device comprises: storage means for storing the remote operation content accepted by the external device; and notification means for notifying the specified communication device of the remote operation content, storage means for storing the remote operation content accepted by the external device; and notification means for notifying the specified communication device of the remote operation content, wherein the relay device rejects storage of the operation content by the storage means or notification of the operation content by the notification means when the remote operation content accepted by the external device is an operation content that is not authorized by the external device, and wherein upon receiving, from a communication device, a notification indicating that an access authorization function is activated and informing that the communication device is in a state of being able to accept a remote operation, the notification means starts notification of the remote operation content for the communication device stored in the storage means, and wherein the communication devices further comprise: internal function processing means; and access management means for checking whether an access authorization function is activated, and accepting the notification of the remote operation content by the notification means to cause the internal function processing means to operate when the access authorization function is activated, and internal function processing means; and access management means for checking whether an access authorization function is activated, and accepting the notification of the remote operation content by the notification means to cause the internal function processing means to operate when the access authorization function is activated, and wherein when there is an interrupt operation for the communication device before completion of the operation of the internal function processing means according to the remote operation content for the communication device stored in the storage means, the access management means deactivates the access authorization function and executes the interrupt operation.