A finger-gesture detection device adapted for a control handle includes a grip portion. The finger-gesture detection device includes a first wearing portion, a plurality of second wearing portions, and a plurality of first sensors. The first wearing portion is adapted to detachably surround the grip portion of the control handle. When the grip portion connects the first wearing portion, the grip portion is positioned on one side of the first wearing portion. The second wearing portions are each independently connected to the first wearing portion. When a force is applied to one of the second wearing portions, the corresponding second wearing portion moves toward the grip portion. The first sensors are respectively disposed on the second wearing portions for detecting positions or movements of the second wearing portions relative to the grip portion. A control assembly and a correction method are also proposed.