PURPOSE: To provide a responsive device of simple structure by retaining a plurality of Peltier elements between at least two metallic plates.

CONSTITUTION: Between two metallic plates 19, 21 with the different coefficients of thermal expansion, Peltier elements 23 are jointed together. Besides, on the counter surfaces of the metallic plates 19, 21, base plates 29, 31 are arranged via respective Peltier elements 25, 27. A power source is connected to the Peltier elements 23, 25, 27. When current is conducted to the Peltier elements 23, 25 so that heat may be generated on the sides jointed to the metallic plate 19, and current is conducted to the Peltier elements 23, 27 so that heat may be absorbed on the sides jointed to the metallic plate 21, then the metallic plate 19 is expanded and the metallic plate 21 is contracted, and so a device 17 is transformed to be projected upward. When the current direction is reversed, then the device 17 is transformed to be projected downward.