A MEMS sensor device provided with a microelectromechanical sensing structure, comprising: - a substrate having a top surface extending in a horizontal plane (xy); - an inertial mass, suspended over said substrate; - elastic coupling elements, elastically connected to said inertial mass so as to enable inertial movement thereof with respect to said substrate as a function of a quantity to be detected along a sensing axis (x) belonging to said horizontal plane (xy); and - sensing electrodes (35a, 35b), capacitively coupled to said inertial mass so as to form at least one sensing capacitor (C 1, C 2), a value of capacitance of which is indicative of said quantity to be detected, further comprising a suspension structure, to which said sensing electrodes (35a, 35b) are rigidly coupled, and to which said inertial mass is elastically coupled through said elastic coupling elements; said suspension structure being connected to an anchorage structure, fixed with respect to said substrate, by means of elastic suspension elements; wherein said suspension structure has a frame-like shape in said horizontal plane (xy) and defines a window inside which said sensing electrodes (35a, 35b) and said inertial mass are arranged, and said anchorage structure comprises anchorage portions (26, 27), fixed with respect to said substrate, which are arranged externally to said suspension structure and coupled to said suspension structure via respective ones of said elastic suspension elements; characterized in that said suspension structure internally includes four electrical-insulation regions, for electrically insulating a first pair of facing frame portions (21a, 21b) of said suspension structure, which are fixedly connected to said sensing electrodes (35a, 35b), from each other and from a second pair of facing frame portions (21c, 21d) of said suspension structure, which are elastically connected to said inertial mass, thereby a first set and a second set of said sensing electrodes (35a, 35b) are set, during operation, at respective biasing voltages different from one another, via a respective conductive path including a first, respectively a second, frame portion of said first pair of frame portions (21a, 21b) of said suspension structure and respective anchorage portions (26, 27) coupled thereto; said inertial mass being electrically biased via a respective conductive path including at least one of the frame portions of said second pair of frame portions (21c, 21d) of said suspension structure and a respective anchorage portion (26, 27) coupled thereto and further through said elastic coupling elements. - a substrate having a top surface extending in a horizontal plane (xy); - an inertial mass, suspended over said substrate; - elastic coupling elements, elastically connected to said inertial mass so as to enable inertial movement thereof with respect to said substrate as a function of a quantity to be detected along a sensing axis (x) belonging to said horizontal plane (xy); and - sensing electrodes (35a, 35b), capacitively coupled to said inertial mass so as to form at least one sensing capacitor (C 1, C 2), a value of capacitance of which is indicative of said quantity to be detected,