A piezoelectric oscillator, and method of making the same, includes an oscillation substrate comprising an oscillating part and a surrounding part, wherein the surrounding part is thinner than the oscillating part, and oscillating electrodes disposed on an upper surface and a lower surface of the oscillating part. The oscillation substrate is configured according to H=400.59×S+1.75±1.5, wherein H=100×(T2/T1) and S=T2/(L1−L2), wherein L1 represents an entire length of the oscillation substrate, L2 represents a length of the oscillating part, T1 represents a thickness of the oscillating part, and T2 represents a step height between the oscillating part and the surrounding part.