An oscillator circuit comprises a piezoelectric vibrator, an amplifier device including inverters provided in a plurality of stages, and an inverter control device. The inverters provided in the plurality of stages includes a performance-variable inverter configured which is operational in both of an initial phase of oscillation startup and a post-startup phase where the oscillation is stabilized and capable of a variable performance depending on whether the initial phase of oscillation startup or the post-startup phase where the oscillation is stabilized, and an ON/OFF inverter which is operational in the initial phase of oscillation startup and disconnected in the post-startup phase where the oscillation is stabilized. The inverter control device have the performance-variable inverter and the ON/OFF inverter both operational and lowers the performance of the performance-variable inverter in the initial phase of oscillation startup, and the inverter control device disconnects the ON/OFF inverter and increases the performance of the performance-variable inverter in the post-startup phase where the oscillation is stabilized.