A bicycle hydraulic operating device comprises a bracket, a hydraulic cylinder, a piston, a lever, a fluid reservoir, and a lid. The bracket is configured to be mounted to a bicycle handlebar. The piston is movably disposed within the hydraulic cylinder. The lever is pivotally provided around a pivot axis relative to the bracket and is operatively coupled to the piston to move the piston within the hydraulic cylinder in response to pivotal movement of the lever. The fluid reservoir is disposed on the bracket and having an opening configured to face substantially in a downward direction in a state where the bracket is mounted to the bicycle handlebar. The lid is configured to cover the opening of the fluid reservoir.