An optical apparatus includes a rectangular optical member provided on an optical axis, a supporting member configured to support the optical member, and a rectangular vibrating device stuck to the optical member close to and in parallel with one of four sides of the optical member and configured to vibrate the optical member in a wave fashion to have a plurality of nodes parallel with the one side. The vibrating device is configured to operate in two or more vibration modes differing from one another at least in number or positions of the plurality of nodes. A support position at which the optical member is supported by the supporting member is a position of a portion of the optical member that corresponds to a node in a vibration mode other than a vibration mode whose amplitude is largest among the two or more vibration modes.