A bicycle operating device comprises a hydraulic unit and a changing unit. The hydraulic unit includes a hydraulic cylinder, a piston, and a reservoir. The hydraulic cylinder includes a cylinder bore. The piston is movably provided in the cylinder bore. The reservoir includes a reserve chamber and a connecting hole. The connecting hole is configured to connect the cylinder bore to the reserve chamber. The changing unit is separately provided from the piston and configured to change a communication state defined between the cylinder bore and the reserve chamber via the connecting hole.