1. A gesture input device, comprising: circuitry configured to receive image information of an object, which is capable of forming a plurality of shapes, detect which of the plurality of shapes is being formed by the object included in the image information, determine one or more candidate gestures based on the detected one of the plurality of shapes being formed by the object, and control notification of an action to be performed next to input each of at least one of the one or more candidate gestures, wherein at least one of the one or more candidate gestures includes two or more sub gestures, and the circuitry is further configured to recognize a first sub gesture based on a detected action performed by the object, predict one or more candidate sub gestures to be input next based on a recognition result of the first sub gesture, and control notification of an action to be performed next to input each of the at least one of the one or more candidate sub gestures.