To provide an optical element supporting device and a lens barrel capable of reducing deflection amount in an optical element and easily securing the optical performance of the optical element, and an aligner capable of accurate projection exposure.

A vertical format lens supporting device 61 is composed of respective movable supporting parts 63a and 63b engaged with the outer peripheral parts of a lens 62 on a lower side and an upper side in a gravity direction and a fixed supporting part 64. The respective supporting parts 63a, 63b and 64 are arranged at equal angle intervals in the circumferential direction of the lens 62. The load of the lens 62 is supported by both supporting parts 63a and 63b, and the tilt of the lens 62 with the supporting parts 63a and 63b as the center of tilt is regulated by the supporting part 64. The rotation of the lens 62 around a Z-axis is regulated by the cooperation of the supporting parts 63a, 63b and 64.