A bicycle display device is configured to accurately verify an amount of
adjustment occurring when performing a fine adjustment of a transmission
position of a transmission device. The bicycle display device is mounted
on a bicycle, and includes a mounting part and a display element. The
mounting part is attachable to a brake bracket of the bicycle. The
display element is supported by the mounting part, and is configured and
arranged to display a fine adjustment display screen for indicating the
amount of adjustment when adjusting the transmission position of a
transmission device such as a rear derailleur.