Provided is a sensing device, which includes a reactive material layer (260) responding to a specific functional group in a fluid, a sensing capacitor (B) including first and second electrodes disposed on and under an insulating layer (230), the first electrode being disposed under the reactive material layer (260), and a field effect transistor including a gate electrode connected with the first electrode of the sensing capacitor. Here, the reactive material layer (260) is formed in a conductive three-dimensional structure to widen a surface area. Thus, the sensing device may have high sensitivity by maximizing a capacitor sharing effect and a change in voltage amount applied to a gate, which may be caused by widening a surface area of the conductive three-dimensional structure with respect to the fluid flow.