To hardly cause damage and failure and to reduce manufacturing processes and man-hours by achieving an actuator with a simple structure using a polymeric material.

A polymer MEMS (microelectromechanical system) actuator 10 with an electrically drivable micro mechanical structure formed on a silicon substrate 11 using the polymeric material includes: a polymer movable part 12 of longitudinal plate shape formed of the polymeric material; a metal heater 13 formed in almost the same shape as the polymer movable part 12 and stuck to the upper face of the polymer movable part 12; and a mirror 14 fixed to the tip part of the metal heater 13 and the polymer movable part 12 and having mirror finished surfaces 14a for reflecting light, on the front and rear faces.