To provide a piezoelectric oscillator in which the size in the thickness direction can be made smaller and the space required for mounting can be made smaller, and a portable telephone and electronic equipment using the piezoelectric oscillator, a resonator package accommodating a piezoelectric resonating element therein, and an IC chip fixed onto a rear surface of the resonator package and having an oscillating circuit therein are provided, and an inner lead portions of a lead frame are fixed onto the rear surface of the resonator package and the resonator package and the IC chip are resin molded except for an outer lead portion of the lead frame.