A bicycle hydraulic component operating device has a main body, a hydraulic cylinder, a piston, an operating lever, a fluid reservoir tank, and a communication port. The main body includes a handlebar mounting portion and a gripping portion. The piston is movably disposed within the hydraulic cylinder. The operating lever is pivotally disposed around a pivot axis relative to the main body. The operating lever is operatively connected with one of the hydraulic cylinder and the piston to generate a hydraulic force in response to pivotal movement of the operating lever relative to the main body. The fluid reservoir tank is in fluid communication with the hydraulic cylinder. The communication port is in communication with the fluid reservoir tank.