A surface acoustic wave device includes a three-dimensional substrate having an annular curved surface enabling to propagate a surface acoustic wave, and an electro-acoustic transducing element, which excites and propagates the surface wave along the surface, and receives the propagated surface wave. The substrate is made of a Li.sub.2B.sub.4O.sub.7, Bi.sub.12SiO.sub.20, LiNbO.sub.3, LiTaO.sub.3, or quartz crystal, and the element propagates the surface wave along a line of intersection between a crystal face of the crystal and the surface, and the line of intersection is defined as an outermost circumferential line of the surface. An environmental difference detecting apparatus uses the device having a plurality of propagating surface zones and compares surface acoustic wave reception signals of electro-acoustic transducing elements in the propagating surface zones of the device with each other, and detects an environmental difference in space portions with which the propagating surface zones come into contact.