A bicycle operating device comprises a base member, a hydraulic cylinder, a piston, and a fluid passageway. The base member is configured to be mounted to a bicycle. The hydraulic cylinder is provided on the base member and includes a cylinder bore. The piston is movably provided in the cylinder bore. The cylinder bore and the piston define a hydraulic chamber. The fluid passageway is connected to the hydraulic chamber. The fluid passageway is provided inside the base member. The fluid passageway has a length longer than a stroke of the piston.