The invention relates to an inertial sensor (1) comprising a substrate extending along a drive excitation direction (x) and a detection direction (y) normal to each other, the device plane being perpendicular to a rotation direction (z), a first drive frame (110) and a second drive frame (120), a first sense frame (210), a second sense frame (220), a sense lever (1000) pivotably mounted around a rotation axis (1001), a sensing system comprising a strain gauge (1600) mechanically stressed by the sense lever it is rotating around the rotation axis. The sense lever includes a central portion (1500), a first arm (1100) and a second arm (1200), the central portion having a dimension along the detection direction called central width, the arms having a dimension along the detection direction called arm width, the central width being at least twice greater than the arm width.