To provide a Lamb-wave type high-frequency resonator that has a high Q value, high phase velocity and superior frequency temperature characteristics.

The Lamb-wave type high-frequency resonator 10 has a liquid crystal substrate 20, an IDT electrode 30 constituted by interposing a first cross finger electrode 31 and a second cross finger electrode 32 into the main surface of the liquid crystal substrate 20 and reflectors 40, 50 arranged on both sides of the traveling direction of the Lamb wave of the IDT electrode 30. If the crossing width between the first cross finger electrode 31 and the second cross finger electrode 32 is W and the wavelength of the Lamb wave is , the crossing width W is set within a range, expressed by 21W54. In addition, the IDT electrode 30 is formed so that the segmentation angle of the liquid crystal substrate 20 and the propagating direction of the Lamb wave become (0, , 0) by Euler angle representation and within a range, in which the angle is expressed as being 35 degrees 47.2 degrees, normalized substrate thickness t/, expressed by a relation between the thickness t of the liquid crystal substrate 20 and the wavelength of the Lamb wave, set to be within a range of 0.176t/1.925.