An in-vehicle device includes: a drive assist unit configured to perform drive assist processing; a display unit configured to display an image in a display area with the image overlapped on a scene in a real space ahead of a vehicle; and a display control unit configured to control the display unit to display, in a normal state while the drive assist processing is performed, an image of a first marker at a vehicle-corresponding position as a position in the display area corresponding to a position where the vehicle is estimated to be positioned in the real space in a predetermined time. The first marker has a first color, the first marker has a first shape that has a smooth outline and fluctuates, and a display position of the first marker varies periodically from the vehicle-corresponding position.