A microelectromechanical mirror device, comprising: a fixed structure defining a cavity; a tiltable structure carrying a reflecting surface, elastically suspended above the cavity and having a main extension in a horizontal plane (xy); elastic elements (26a-26b, 34a-34d) coupled to said tiltable structure; and at least one first pair of driving arms (32a, 32b), carrying respective regions of piezoelectric material, to be biased to cause rotation of the tiltable structure about at least one first axis of rotation parallel to a first horizontal axis (x) of said horizontal plane (xy), elastically coupled to the tiltable structure and interposed between the tiltable structure and the fixed structure, wherein said driving arms (32a, 32b) having, along an orthogonal axis (z) transverse to said horizontal plane (xy), a thickness smaller than that of at least some of the elastic elements (26a-26b, 34a-34d) coupled to said tiltable structure, and wherein said elastic elements (26a-26b, 34a-34d) comprise: elastic decoupling elements (34a, 34b), which couple said tiltable structure to said driving arms (32a, 32b) on opposite sides and in the proximity of the first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about an axis parallel to said first axis of rotation; and elastic suspension elements (26a, 26b), which elastically couple said tiltable structure to said fixed structure at said first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about said first axis of rotation, said elastic suspension elements (26a, 26b) extending along said first axis of rotation, between a central portion of opposite sides of the tiltable structure and said fixed structure. a fixed structure defining a cavity; a tiltable structure carrying a reflecting surface, elastically suspended above the cavity and having a main extension in a horizontal plane (xy); elastic elements (26a-26b, 34a-34d) coupled to said tiltable structure; and at least one first pair of driving arms (32a, 32b), carrying respective regions of piezoelectric material, to be biased to cause rotation of the tiltable structure about at least one first axis of rotation parallel to a first horizontal axis (x) of said horizontal plane (xy), elastically coupled to the tiltable structure and interposed between the tiltable structure and the fixed structure, wherein said driving arms (32a, 32b) having, along an orthogonal axis (z) transverse to said horizontal plane (xy), a thickness smaller than that of at least some of the elastic elements (26a-26b, 34a-34d) coupled to said tiltable structure, and wherein said elastic elements (26a-26b, 34a-34d) comprise: elastic decoupling elements (34a, 34b), which couple said tiltable structure to said driving arms (32a, 32b) on opposite sides and in the proximity of the first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about an axis parallel to said first axis of rotation; and elastic suspension elements (26a, 26b), which elastically couple said tiltable structure to said fixed structure at said first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about said first axis of rotation, said elastic suspension elements (26a, 26b) extending along said first axis of rotation, between a central portion of opposite sides of the tiltable structure and said fixed structure. elastic decoupling elements (34a, 34b), which couple said tiltable structure to said driving arms (32a, 32b) on opposite sides and in the proximity of the first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about an axis parallel to said first axis of rotation; and elastic suspension elements (26a, 26b), which elastically couple said tiltable structure to said fixed structure at said first axis of rotation and are rigid with respect to movements out of the horizontal plane (xy) and compliant to torsion about said first axis of rotation, said elastic suspension elements (26a, 26b) extending along said first axis of rotation, between a central portion of opposite sides of the tiltable structure and said fixed structure.