Crystal oscillator

A crystal oscillator comprising:

• an oscillating stage which has a resonance circuit including a crystal unit and a capacitor, an inverting amplifier, and a feedback resistor connected to said inverting amplifier, said inverting amplifier feeding back and amplifying a resonance frequency component of said resonance circuit to output the resonance frequency component;
• and
• a buffering stage for outputting an output of said oscillating stage after reducing an amplitude thereof,
• said buffering stage including first and second MOS FETs of same conductive type arranged in series between an electric power supply and a reference potential,
• wherein a signal at an output terminal of said inverting amplifier is impressed to a gate of said first MOS FET, a signal at an input terminal of said inverting amplifier is impressed to a gate of said second MOS FET, and an output is obtained from a connecting point of said first and second MOS FETs.