A SAW resonator which, using a quartz crystal substrate with Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, and 42.79°≦|105|≦49.57°, includes an IDT which excites a stop band upper end mode SAW, and grooves hollowed out of the substrate positioned between electrode fingers configuring the IDT, wherein, when the wavelength of the SAW is λ and the depth of the inter-electrode finger grooves is G, λ and G satisfy the relationship of 0.01λ≦G and wherein, when the line occupation rate of the IDT is η, the groove depth G and line occupation rate η satisfy the relationships of −2.0000×G/λ+0.7200≦η≦−2.5000×G/λ+0.7775 provided that 0.0100λ≦G≦0.0500λ, −3.5898×G/λ+0.7995≦η≦−2.5000+G/λ+0.7775 provided that 0.0500λ