A device for measuring a variation (ΔCX) of a capacitance (CX), includes: elements for charging the capacitance (CX) on the basis of a supply voltage (VCC). elements for discharging the capacitance (CX) into a reference capacitance (CS) in a fixed number of discharges (x), elements for measuring a voltage (VS) and for detecting a threshold of voltage (VTH) across the terminals of the reference capacitance (CS). elements for charging with current (IC) the reference capacitance (CS) on the basis of the supply voltage (VCC) for a duration (t), after the transfer of charge from the capacitance (CX) into the reference capacitance (CS), and elements for measuring the variation between the duration (t) with respect to a previously measured duration so as to estimate the variation (ΔCX) of the capacitance (CX).