A sensing device including a transistor, at least one response electrode, and a receptor is provided. The transistor includes a gate end, a source end, a drain end, and a semiconductor layer. The source end and the drain end are located on the semiconductor layer, and the gate end is located between the source end and the drain end. The at least one response electrode is disposed opposite to the gate end of the transistor and spaced apart from the transistor. The receptor is bonded onto the at least one response electrode. When a voltage is applied to the at least one response electrode, an electric field between the at least one response electrode and the gate end of the transistor is F, and F≧1 mV/cm. |