A piezoelectric/electrostrictive device includes: a ceramic substrate having a frame-like thick portion, a thin diaphragm portion, and a cavity formed by the thick portion and the thin diaphragm portion to communicate with the outside; and a piezoelectric/electrostrictive element having a layered structure including a lower electrode, a piezoelectric/electrostrictive film, and an upper electrode. Furthermore, the thin diaphragm portion is provided with an outward protruding arch shape, and in the piezoelectric/electrostrictive element, there remains a tensile stress parallel to a fixed surface of the element to the thin diaphragm portion. The piezoelectric/electrostrictive device is superior in response, and in the device high-precision (high-resolution, high-sensitivity) detection is possible, while effectively preventing decay of vibration of a thin diaphragm portion and maintaining displacement (amplitude) to be high.