A bicycle operating device comprises a base member and an operating member. The operating member includes an adapter, an operating lever, and an operating shaft. The adapter includes a center cross sectional area and a first cross sectional area. The center cross sectional area is defined on a center cross sectional plane perpendicular to the pivot axis. The first cross sectional area is defined on a first cross sectional plane perpendicular to the pivot axis. The first cross sectional area is offset from the center cross sectional area in a second direction parallel to the pivot axis. The first cross sectional area is larger than the center cross sectional area.