An angular velocity sensor includes a sensor element having a shape defined in an XYZ space, and can detect an angular velocity about a Z axis. The sensor element includes a support body extending in a direction of an X axis, an arm connected with the support body, and a weight connected with the arm. The arm has a first end connected with the support body and a second end connected with the weight. The arm has substantially a J-shape including a first arm portion extending in a direction of a Y axis from the first end to a first corner, a second arm portion extending in the direction of the X axis from the first corner to a second corner, and a third arm portion extending in the direction of the Y axis from the second corner to the second end. The length of the arm in the direction of the X axis is larger than the length of the weight in the direction of the X axis. This angular velocity sensor can improve the sensibility to angular velocity about the Z axis.