A piezoelectric/electrostrictive device includes a ceramic substrate and a piezoelectric/electrostrictive element formed on the ceramic substrate. The ceramic substrate includes fixed sections which have a large thickness, a pair of thin plate sections which are formed continuously from the fixed sections and which are thinner than the fixed sections, and movable sections which are provided at ends of the pair of thin plate sections. An additional member is used at least between the pair of thin plate sections and the movable sections. The additional member is a porous member or at least one columnar member.