A piezoelectric oscillator includes an inverter amplifier, a first load impedance constituting together with the inverter amplifier a connection circuit that is inserted between the power supply and the ground, a piezoelectric resonator being inserted between the input of the inverter amplifier and the ground, a second load impedance being serially inserted and connected between the input of the inverter amplifier and a connecting point of the inverter amplifier and the first load impedance, and a resistor being connected between the input and an output of the inverter amplifier. |