A piezo-oscillator reduced in current consumption and size, comprising a crystal oscillator as a piezoelectric vibrator, an oscillation circuit, a plurality of surface mounted heaters, and a temperature control circuit for controlling the heating temperatures of the heaters, all mounted on a printed circuit board, wherein the case and lead terminals of the piezoelectric vibrator are simultaneously heated respectively by separate heaters so that the piezoelectric vibrator, the oscillation circuit and the temperature control circuit can be heated at the same time.