Unintended motion of a displayed object is prevented by rapidly detecting a state in which an operator becomes unable to operate an operating unit. Provided is an operation input unit including a display a head-mounted unit an operating unit to which an operating signal for a displayed object displayed on the display is input a relative-position detecting section that detects the relative position between the head-mounted unit and the operating unit and a control unit that controls the displayed object by switching between a first control mode in which the motion of the displayed object is controlled in accordance with an operating signal input to the operating unit and a second control mode in which the motion of the displayed object is controlled by limiting an operating signal input to the operating unit on the basis of the relative position detected by the relative-position detecting section.