A display device includes a display unit, a first display control unit, a title string storing unit, a concatenated string creating unit, a determining unit, a navigation string creating unit, and a second display control unit. The display unit includes a first portion and a second portion. The first display control unit is configured to display one of a plurality of screen images on the first portion. The plurality of screen images includes a base screen image. The first display control unit changes a screen image to display from one to another of the plurality of screen images along a screen navigation path starting from the base screen image. The title string storing unit is configured to store a plurality of title strings. Each title string indicating one of the plurality of screen images. The concatenated string creating unit is configured to create a concatenated string including the title strings each corresponding to a screen image which is positioned in a part of the screen navigation path from the base screen image to a current screen image that is displayed on the first portion currently. The determining unit is configured to determine whether or not the concatenated string is too large to be displayed entirely on the second portion. The navigation string creating unit is configured to create a navigation string by deleting an at least one of the title strings from the concatenated string when the determining unit determines that the concatenated string is too large to be displayed entirely on the second portion. The second display control unit is configured to display the navigation string on the second portion.