A piezoelectric/electrostrictive device comprises a pair of mutually opposing thin plate sections, a movable section, and a fixation section for supporting the thin plate sections and the movable section. Piezoelectric/electrostrictive elements are arranged on the pair of thin plate sections. A hole is formed by the inner walls of the pair of thin plate sections, an inner wall of the movable section, and an inner wall of the fixation section. A through-hole having a rectangular cross section is formed over a range from a forward end surface of the movable section to the hole to realize a light weight of the movable section.