A cell driving type piezoelectric/electrostrictive actuator comprises: one or a plurality of cells defined by a wall portion including side walls, a ceiling wall and a bottom wall: side walls, the ceiling wall and the bottom wall being connected to form a space as cell, at least two side walls facing each other comprising piezoelectric/electrostrictive operation portions, the piezoelectric/electrostrictive operation portions being displaced to change a volume of the cell, wherein at least one pore is disposed in the wall portion other than at least two side walls facing each other and comprising piezoelectric/electrostrictive operation portions, and wherein all inner surfaces of the wall portion defining each cell are coated with one or more layers of seamless thin films. The method for preparing the same is also disclosed.