In a truss type actuator having two piezoelectric devices provided for crossing at right angle and driven by two alternating driving signals having a predetermined phase difference between them for driving a chip member along a predetermined elliptic trail (including a circular trail). The piezoelectric devices are contacted by protrusions having a high rigidity and formed on contacting faces of the chip member and a base member for holding the piezoelectric devices, and fixed by adhesive having a low rigidity and filled around the protrusions. Thereby, one of the piezoelectric device hardly receives a reaction force from another piezoelectric device due to the displacement thereof.