An oscillating mirror element (6, 7, 206, 306, 506, 606, 706, 806a, 806b, 806c) comprising: a mirror portion; a drive portion (61b, 62, 62b, 361b) that drives the mirror portion; a strain sensor capable of detecting an amount of displacement of the mirror portion; and a base (64, 264, 364, 560, 561c, 562c, 660, 661c) including a mirror beam portion (64e, 564e, 664e, 764e) provided with the mirror portion, a sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) provided with the strain sensor, and a body portion that supports the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) and is provided with the drive portion (61b, 62, 62b, 361b), characterized in that the body portion of the base (64, 264, 364, 560, 561c, 562c, 660, 661c) includes: an outer frame portion on which the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) are inwardly arranged, and a pair of beam support portions that is connected to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) and has first ends extending toward the drive portion (61b, 62, 62b, 361b) and second ends connected to the outer frame portion, wherein the pair of beam support portions is perpendicular to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f). a mirror portion; a drive portion (61b, 62, 62b, 361b) that drives the mirror portion; a strain sensor capable of detecting an amount of displacement of the mirror portion; and a base (64, 264, 364, 560, 561c, 562c, 660, 661c) including a mirror beam portion (64e, 564e, 664e, 764e) provided with the mirror portion, a sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) provided with the strain sensor, and a body portion that supports the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) and is provided with the drive portion (61b, 62, 62b, 361b), characterized in that the body portion of the base (64, 264, 364, 560, 561c, 562c, 660, 661c) includes: an outer frame portion on which the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) are inwardly arranged, and a pair of beam support portions that is connected to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) and has first ends extending toward the drive portion (61b, 62, 62b, 361b) and second ends connected to the outer frame portion, wherein the pair of beam support portions is perpendicular to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f). an outer frame portion on which the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) are inwardly arranged, and a pair of beam support portions that is connected to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f) and has first ends extending toward the drive portion (61b, 62, 62b, 361b) and second ends connected to the outer frame portion, wherein the pair of beam support portions is perpendicular to each of the mirror beam portion (64e, 564e, 664e, 764e) and the sensor beam portion (64f, 264f, 364f, 564f, 664f, 764f).