1. A projector, comprising: a projection part that projects a menu image including at least one part according to an image signal; a selection part that causes a user to select a language type of the menu image; a menu image processing part that generates the image signal so that a character array of the selected language type can appear in the menu image as the part; an additional function part that outputs an image data set to a network line; the additional function part outputting the image data set corresponding to the selected language type to the network line, so that a computer connected to the additional function part through the network line can display data relating to the projector on a monitor screen of the computer, with the selected language type.