Abstract: A SAW device utilizing elastic surface waves, in which the Q value indicating resonance sharpness is high, and which presents excellent frequency temperature characteristics and short-term frequency stability. In a SAW device according to the present invention, an IDT and two reflectors are in parallel in the propagation direction of the phase of the elastic surface waves. The IDT and reflectors are disposed to cover the power flow direction, which is the propagation direction of energy of the elastic surface waves, whereby the energy of the elastic surface waves is efficiently confined. Moreover, it becomes possible to manufacture the SAW device utilizing a piezoelectric crystal in which angle .theta. and angle .psi. indicating excellent frequency temperature characteristics are 25 to 45 degrees and 40 to 47 degrees, respectively. It is also possible to manufacture the SAW device utilizing a piezoelectric crystal where angle .psi. is related to angle .theta. such that .theta.=2.775.times.(.psi.-32.5)+6.