The invention provides a piezoelectric oscillator that allows for fine adjustment of the frequency after resin molding, a manufacturing method therefor, and a mobile phone and an electronic apparatus using the piezoelectric oscillator. The piezoelectric oscillator can include a resonator package, in which a piezoelectric resonator element is housed, and a semiconductor device, in which an oscillation circuit that is electrically connected to the resonator package is incorporated. The resonator package and the semiconductor device can be fixed to corresponding different surfaces of an island portion of a lead frame, and resin molding is performed so that a transparent lid of the resonator package is exposed to the outside.