A spring powered ambulatory infusion apparatus includes a syringe module and an actuator module. The syringe module includes a syringe barrel for containing infusion medicine and a piston for discharging the infusion medicine. The actuator module includes compression springs to move the piston when the springs expand. Each spring is bent to reduce its overall length, and have a U-shape in its compressed state and a J-shape in its expanded state. When each spring expands, one end of the spring moves to push the piston while the other end is stationary such that the shape thereof changes from the U-shape to the J-shape.
