A longitudinal quartz crystal resonator has at least two vibrating arms arranged in parallel to each other to undergo a longitudinal vibration. The vibrating arms are connected together at both ends thereof by connecting sections. A pair of bridge sections extend from central parts of respective ones of the outermost vibrating arms and are connected to flexional sections. The bridge sections are supported through surrounding frame sections by a bottom mount section. The flexional sections are connected to the frame sections so as to form surrounding openings. By such construction, an equivalent inductance and a series resistance are reduced in the longitudinal quartz crystal resonator so as to eliminate vibrating energy loss.