To provide a small-sized oscillator at a low cost while withstanding mechanical vibration by cutting off a lead electrode being a small electrode at a rear side of a lowermost layer of the oscillator with terminals and a case fitted thereto so as to fine-adjust the oscillating frequency.

A metallic case 1 covers the upper part of a ceramic board 2 on which required components are mounted and a dielectric board 3 is arranged to a bottom face of the board 2. A crystal vibrator 4, a resistor 5, a capacitor 6, a mini-mold transistor(TR) 7 and chip capacitors 8, 9 are mounted on the board 2 and a circuit is formed by a wiring pattern. A flat electrode 10 is formed on an upper side of the dielectric board 3, plural electrodes 11, 12 with a small area are connected in series and the small electrodes connected in series are connected in parallel. Then a lead electrode 13 is provided and the capacitance is changed by cutting off the lead electrodes 14, 15 and/or 16. In the frequency adjustment of the oscillator, the load capacitance is adjusted as desired by cutting off the lead electrodes 14, 15 and/or 16 connecting to the small electrodes 11, 12 by means of a laser or the like.