To provide an oscillator capable of obtaining a more stable oscillation frequency by reducing influence due to the variation of an element characteristic, and the fluctuation in temperature or power source voltage.

The oscillator comprises: a variable frequency oscillating means 21 for controlling the oscillation frequency fosc in response to the electric current or voltage to be inputted; a frequency-voltage converting means 22 for outputting the voltage V1 corresponding to the oscillation frequency fosc of the variable frequency oscillating means 21; and a comparison means 23 for comparing the output voltage V1 of the frequency-voltage converting means 21 with a reference voltage Vref2 so as to output the difference. The output of the comparison means 23 is supplied to the variable frequency oscillating means 21 so as to control the oscillation frequency fosc of the variable frequency oscillating means 21.