An ultrasonic sensor includes: when two orthogonal axes are referred to as an X axis and a Y axis and a plane formed by the X axis and the Y axis is referred to as an XY plane, a substrate disposed across the XY plane; a plurality of spaces formed in the substrate in at least one direction of an X-axis direction and a Y-axis direction; a vibrating plate that is provided on the substrate such that the spaces are closed and that has a first surface on the substrate side and a second surface facing the first surface; and a piezoelectric element that is provided at a portion on the second surface side of the vibrating plate that corresponds to the space, and that transmits/receives an ultrasonic wave. At least some of the spaces are arranged to form a zigzag shape.