An electromagnetic measuring device includes a hydraulic body defining a duct for a flow of a liquid, and a flow sensor on the hydraulic body that includes an electromagnetic arrangement for generating an electromagnetic field through the duct in a direction transverse to the flow of the liquid, and detection arrangement including two electrical detection elements for detecting a potential difference induced by the flow of the liquid through the electromagnetic field. The detection elements are associated to one and the same face of a substrate, which extends on the outside of the duct in a position corresponding to a first side of the duct. The first side of the duct has two through openings, each of which is in a position corresponding to a respective electrical detection element.