The self-polarised quartz oscillator circuit comprises an amplifier with an output which is connected to a first electrode of the quartz and an input which is connected to a second electrode of the quartz, an output capacitor which is connected to the first electrode of the quartz and an input capacitor which is connected to the second electrode of the quartz. The amplifier is polarised by a current through a MOS polarisation transistor, which is generated in an amplitude regulation assembly which comprises also an amplitude regulation stage. The second electrode of the quartz is connected to the gate of the polarisation transistor and to the amplitude regulation stage in order to modulate the polarisation current and to regulate the oscillation amplitude of the quartz.