A resonator comprising: a vibrator including a silicon substrate, at least one electrode (E2, E21 to E24) that has a face facing a surface of the silicon substrate and extending with long sides in a lengthwise direction and short sides in a widthwise direction, and a piezoelectric body that is formed between the silicon substrate and the electrode (E2, E21 to E24) and that produces a contour vibration in a plane along the surface of the silicon substrate in accordance with a voltage applied to the electrode (E2, E21 to E24) so that the contour vibration has a node that extends along the lengthwise direction of the electrode (E2, E21 to E24); a holder that surrounds at least a portion of the vibrator; and a holding arm that connects the vibrator and the holder to each other, wherein the vibrator includes at least one rectangular vibration region (121, 122a to 122d) that has a long side parallel to the node of the contour vibration of the piezoelectric body and a short side orthogonal to the node of the contour vibration of the piezoelectric body and corresponding to a half-wavelength of the contour vibration, characterized in that the vibrator is set within a range that satisfies W/T ≥ 4 and y = − 0.85 m Ω ⋅ cm ⋅ μm × 1 / T + 0.57 m Ω ⋅ cm ± 0.05 m Ω ⋅ cm where T is a thickness of the silicon substrate in a direction orthogonal to the surface thereof, W is a width of the short side of the vibration region (121, 122a to 122d), and y is a resistivity of the silicon substrate. a vibrator including a silicon substrate, at least one electrode (E2, E21 to E24) that has a face facing a surface of the silicon substrate and extending with long sides in a lengthwise direction and short sides in a widthwise direction, and a piezoelectric body that is formed between the silicon substrate and the electrode (E2, E21 to E24) and that produces a contour vibration in a plane along the surface of the silicon substrate in accordance with a voltage applied to the electrode (E2, E21 to E24) so that the contour vibration has a node that extends along the lengthwise direction of the electrode (E2, E21 to E24); a silicon substrate, at least one electrode (E2, E21 to E24) that has a face facing a surface of the silicon substrate and extending with long sides in a lengthwise direction and short sides in a widthwise direction, and a piezoelectric body that is formed between the silicon substrate and the electrode (E2, E21 to E24) and that produces a contour vibration in a plane along the surface of the silicon substrate in accordance with a voltage applied to the electrode (E2, E21 to E24) so that the contour vibration has a node that extends along the lengthwise direction of the electrode (E2, E21 to E24); a holder that surrounds at least a portion of the vibrator; and a holding arm that connects the vibrator and the holder to each other, wherein the vibrator includes at least one rectangular vibration region (121, 122a to 122d) that has a long side parallel to the node of the contour vibration of the piezoelectric body and a short side orthogonal to the node of the contour vibration of the piezoelectric body and corresponding to a half-wavelength of the contour vibration, characterized in that the vibrator is set within a range that satisfies W/T ≥ 4 and y = − 0.85 m Ω ⋅ cm ⋅ μm × 1 / T + 0.57 m Ω ⋅ cm ± 0.05 m Ω ⋅ cm where T is a thickness of the silicon substrate in a direction orthogonal to the surface thereof, W is a width of the short side of the vibration region (121, 122a to 122d), and y is a resistivity of the silicon substrate.