In an angular velocity sensor, driven mass portions are disposed on a surface of a base plate at point-symmetrical locations with respect to a central point O. The driven mass portions are connected to a coupling beam to be interconnected. The coupling beam is flexibly supported through connecting portions and driven beam. Detecting mass portions are disposed inside the driven mass portions, and the detecting mass portions are supported by detecting beams to be displaceable in the Z-axis direction. Two adjacent ones of the driven mass portions in the circumferential direction are vibrated by vibration generation portions in opposite phases to each other. When angular velocities are exerted in such a state, the detecting mass portions are caused to displace and vibrate in the direction of thickness of the base plate. Displacement detecting portions detect displacements of the detecting mass portions in the direction of the thickness.