A crane information display system comprising: an information display unit that is mounted on a vehicle body frame of a crane, and a terminal device that mounts a camera to capture an image of the crane with the camera and obtain a camera image; wherein the terminal device comprises: a crane information acquisition unit that is configured to read display information of the information display unit from the camera image and is configured to acquire information about the crane; a position/orientation calculation unit that is configured to read display information of the information display unit, is configured to acquire information about a reference shape of the information display unit and a mounting position of the information display unit on the crane from the camera image, is configured to extract a contour shape of the information display unit reflected in the camera image, and is configured to calculate a position and an orientation of the crane based on information about the reference shape of the information display unit, the mounting position of the information display unit, and the contour shape of the information display unit; an information processing unit that is configured to convert the information about the crane acquired by the crane information acquisition unit into three-dimensional image information corresponding to the position and orientation of the crane calculated by the position/orientation calculation unit; and an image display unit that is configured to overlay the information about the crane converted by the information processing unit on the camera image and is configured to display the information. an information display unit that is mounted on a vehicle body frame of a crane, and a terminal device that mounts a camera to capture an image of the crane with the camera and obtain a camera image; wherein the terminal device comprises: a crane information acquisition unit that is configured to read display information of the information display unit from the camera image and is configured to acquire information about the crane; a position/orientation calculation unit that is configured to read display information of the information display unit, is configured to acquire information about a reference shape of the information display unit and a mounting position of the information display unit on the crane from the camera image, is configured to extract a contour shape of the information display unit reflected in the camera image, and is configured to calculate a position and an orientation of the crane based on information about the reference shape of the information display unit, the mounting position of the information display unit, and the contour shape of the information display unit; an information processing unit that is configured to convert the information about the crane acquired by the crane information acquisition unit into three-dimensional image information corresponding to the position and orientation of the crane calculated by the position/orientation calculation unit; and an image display unit that is configured to overlay the information about the crane converted by the information processing unit on the camera image and is configured to display the information. a crane information acquisition unit that is configured to read display information of the information display unit from the camera image and is configured to acquire information about the crane; a position/orientation calculation unit that is configured to read display information of the information display unit, is configured to acquire information about a reference shape of the information display unit and a mounting position of the information display unit on the crane from the camera image, is configured to extract a contour shape of the information display unit reflected in the camera image, and is configured to calculate a position and an orientation of the crane based on information about the reference shape of the information display unit, the mounting position of the information display unit, and the contour shape of the information display unit; an information processing unit that is configured to convert the information about the crane acquired by the crane information acquisition unit into three-dimensional image information corresponding to the position and orientation of the crane calculated by the position/orientation calculation unit; and an image display unit that is configured to overlay the information about the crane converted by the information processing unit on the camera image and is configured to display the information.