A fluid sensing device is provided, including a main body and a light sensing unit. The main body includes a casing and a rotary member. A containing chamber is formed in the casing. The rotary member is rotatably disposed in the casing, and the rotary member has at least one transparent portion. A fluid flows into the containing chamber to drive the rotary member rotating around a central axis. The light sensing unit includes a first light transceiver module and a second light transceiver module disposed near the main body in an asymmetrical manner with respect to the central axis to transmit and receive the light passing through the translucent portion.