An angular velocity sensor includes a base portion, three arm portions that extend as one piece from the base portion to an approximately same direction, a piezoelectric film formed on one surface of each of the arm portions, drive electrodes for excitation formed on the piezoelectric films of at least two outer arm portions, and detection electrodes for angular velocity detection formed on the piezoelectric film of at least a center arm portion. Among the three arm portions, the two outer arm portions are excited in phase, and the center arm portion is excited in opposite phase with the two outer arm portions. The drive electrodes excite the arm portions in a first direction vertical to surfaces on which the piezoelectric films are formed. The detection electrodes detect a vibration in a second direction parallel to the surfaces on which the piezoelectric films of the arm portions are formed.