An angular velocity sensor includes an angular velocity sensor element, a drive circuit, a detection circuit, and a reference potential supply circuit. The angular velocity sensor element has a monitor electrode, a drive electrode, a sense electrode, and a weight. The reference potential supply circuit supplies a reference potential to the angular velocity sensor element. The reference potential supply circuit has a first CV converter, a second CV converter, a comparator, and a reference potential adjustment circuit. The first CV converter is connected to the monitor electrode. The second CV converter is connected to the sense electrode. The comparator compares a frequency of a signal being output from the first CV converter with a frequency of a signal being output from the second CV converter, and outputs a signal depending on a result of the comparison.