Capacitive detector and measuring device integrating it; the detector including: a ribbon made of a dielectric material, first and second electrodes in the form of combs formed on a first surface of said ribbon and a third electrode formed on the other surface of said ribbon opposite said first and second electrodes; the thickness (e) of the dielectric ribbon is less than or equal to said determined period (λ) divided by four times PI, i.e.: λ/4π≧e; and the ratio resulting from the division, as numerator, of the capacitance (C) between two adjacent branches of said first and second electrodes in the presence of at least one fluid with a dielectric permittivity (∈f) and, as denominator, by the dielectric permittivity (∈f) of the fluid multiplied by the capacitance (Co) between the two adjacent branches of the first and second electrodes in the presence of the vacuum is greater than or equal to one, i.e.: C/(∈f*Co)≧1. Method for manufacturing a detector fulfilling the above conditions.