An ultrasonic motor, comprising: an annular vibrator; and an annular moving member arranged to be brought into pressure-contact with the annular vibrator, wherein the annular vibrator comprises: an annular vibrating plate; and an annular piezoelectric element arranged on a first surface of the annular vibrating plate, the annular vibrating plate being brought into contact with the annular moving member on a second surface on a side opposite to the first surface, wherein the annular piezoelectric element comprises: an annular piezoelectric ceramic piece; a common electrode arranged on a surface of the annular piezoelectric ceramic piece facing the annular vibrating plate so as to be sandwiched between the annular piezoelectric ceramic piece and the annular vibrating plate; and a plurality of electrodes arranged on a surface of the annular piezoelectric ceramic piece opposite to the surface on which the common electrode is arranged, wherein the annular piezoelectric ceramic piece contains lead in a content of less than 1,000 ppm, wherein the plurality of electrodes comprise two drive phase electrodes, one or more non-drive phase electrodes, and one or more phase detection electrodes, wherein the second surface of the annular vibrating plate includes X radially extending groove regions, and when an outer diameter of the annular vibrating plate is set to 2R in a unit of mm, the X is a natural number satisfying 2R/0.85-5≤X≤2R/0.85+15 and the outer diameter 2R is 57 mm or more, wherein a ratio between an average value L top of a length in a circumferential direction on an outer diameter side of a wall region that separates the adjacent groove regions from each other and an average value L btm of a length in a circumferential direction on an outer diameter side of the groove regions falls within a range of 1.45≤L top /L btm ≤1.85, and wherein, when center depths of the groove regions in the X portions are represented by D 1 to D X in order in the circumferential direction, the D 1 to the D X change so as to follow a curve obtained by superimposing one or more sine waves on one another, the groove regions reaching a local maximum in 12 or more regions in the change of the center depth and the groove regions reaching a local minimum in 12 or more regions in the change of the center depth, the groove regions reaching the local maximum and the groove regions reaching the local minimum being prevented from being adjacent to each other. an annular vibrator; and an annular moving member arranged to be brought into pressure-contact with the annular vibrator, wherein the annular vibrator comprises: an annular vibrating plate; and an annular piezoelectric element arranged on a first surface of the annular vibrating plate, the annular vibrating plate being brought into contact with the annular moving member on a second surface on a side opposite to the first surface, an annular vibrating plate; and an annular piezoelectric element arranged on a first surface of the annular vibrating plate, the annular vibrating plate being brought into contact with the annular moving member on a second surface on a side opposite to the first surface, wherein the annular piezoelectric element comprises: an annular piezoelectric ceramic piece; a common electrode arranged on a surface of the annular piezoelectric ceramic piece facing the annular vibrating plate so as to be sandwiched between the annular piezoelectric ceramic piece and the annular vibrating plate; and a plurality of electrodes arranged on a surface of the annular piezoelectric ceramic piece opposite to the surface on which the common electrode is arranged, an annular piezoelectric ceramic piece; a common electrode arranged on a surface of the annular piezoelectric ceramic piece facing the annular vibrating plate so as to be sandwiched between the annular piezoelectric ceramic piece and the annular vibrating plate; and a plurality of electrodes arranged on a surface of the annular piezoelectric ceramic piece opposite to the surface on which the common electrode is arranged, wherein the annular piezoelectric ceramic piece contains lead in a content of less than 1,000 ppm, wherein the plurality of electrodes comprise two drive phase electrodes, one or more non-drive phase electrodes, and one or more phase detection electrodes, wherein the second surface of the annular vibrating plate includes X radially extending groove regions, and when an outer diameter of the annular vibrating plate is set to 2R in a unit of mm, the X is a natural number satisfying 2R/0.85-5≤X≤2R/0.85+15 and the outer diameter 2R is 57 mm or more, wherein a ratio between an average value L top of a length in a circumferential direction on an outer diameter side of a wall region that separates the adjacent groove regions from each other and an average value L btm of a length in a circumferential direction on an outer diameter side of the groove regions falls within a range of 1.45≤L top /L btm ≤1.85, and wherein, when center depths of the groove regions in the X portions are represented by D 1 to D X in order in the circumferential direction, the D 1 to the D X change so as to follow a curve obtained by superimposing one or more sine waves on one another, the groove regions reaching a local maximum in 12 or more regions in the change of the center depth and the groove regions reaching a local minimum in 12 or more regions in the change of the center depth, the groove regions reaching the local maximum and the groove regions reaching the local minimum being prevented from being adjacent to each other.