An object of the present invention is to provide an actuator allowing a control of displacement and configured to offer a high degree of freedom in designing, and a drive device and an imaging device including the actuator. To achieve the object, an actuator is adopted including a movable part deformable in accordance with heat generation and a control section controlling the amount of deformation of the movable part. In the actuator, the movable part is structured with a plurality of portions including a base portion, a force generating portion, and a heat generating portion being stacked, the force generating portion generating force in accordance with heating, the heat generating portion generating heat in accordance with a current supply. The control section controls the amount of deformation of the movable part by controlling the current supply to the heat generating portion based on an electrical resistance in the heat generating portion.