An optical apparatus such as a varifocal fluidic lens is provided. Optical apparatus includes a spacer frame, optical fluid, an elastic membrane, an actuator, an actuator frame, and a thermally deformable frame. Spacer frame defines an internal space including a lens portion and a driving portion that connect to each other, and the driving portion is disposed to surround the lens portion disposed in the center area of the internal space. Optical fluid is filled in the internal space defined by the spacer frame. The elastic membrane is attached on a surface of the spacer frame, to cover a side of the internal space, and the thermally deformable plate is attached on the other surface of the spacer frame, to cover the other side of the internal space. The thermally deformable plate deforms to increase or decrease a volume of the internal space according to a change in temperature.