An operation system, comprising: a work vehicle having a work apparatus, a control apparatus configured to control the work apparatus, a plurality of remote operation terminals configured to operate the work apparatus, respectively, and an information relay device connected to the control apparatus and to the remote operation terminals, characterized in that the operation system is configured such that a primary setting related to a working condition of the work apparatus is allowed to be changed by transmitting a radio wave signal from one of the remote operation terminals to the information relay device; and when the primary setting is changed by one of the plurality of remote operation terminals, the change of the primary setting is also reflected in the other of the remote operation terminals by transmitting a radio wave signal from information relay device to the other of the remote operation terminals, wherein each of the remote operation terminals includes a switching tool; and the operation system is configured such that only one of the remote operation terminals which is selected by the switching tool is allowed to change the primary setting, and when the primary setting is changed by the one of the remote operation terminals, the change of the primary setting is also reflected in the other of the remote operation terminals, and wherein each of the remote operation terminals includes an image display; and the operation system is configured such that, when the primary setting is changed by the one of the remote operation terminals, a screen in which a content to be reflected in the primary setting is displayed on the image display of each of the other of the remote operation terminals. a work vehicle having a work apparatus, a control apparatus configured to control the work apparatus, a plurality of remote operation terminals configured to operate the work apparatus, respectively, and an information relay device connected to the control apparatus and to the remote operation terminals, characterized in that the operation system is configured such that a primary setting related to a working condition of the work apparatus is allowed to be changed by transmitting a radio wave signal from one of the remote operation terminals to the information relay device; and when the primary setting is changed by one of the plurality of remote operation terminals, the change of the primary setting is also reflected in the other of the remote operation terminals by transmitting a radio wave signal from information relay device to the other of the remote operation terminals, wherein each of the remote operation terminals includes a switching tool; and the operation system is configured such that only one of the remote operation terminals which is selected by the switching tool is allowed to change the primary setting, and when the primary setting is changed by the one of the remote operation terminals, the change of the primary setting is also reflected in the other of the remote operation terminals, and wherein each of the remote operation terminals includes an image display; and the operation system is configured such that, when the primary setting is changed by the one of the remote operation terminals, a screen in which a content to be reflected in the primary setting is displayed on the image display of each of the other of the remote operation terminals.