OPTICAL DEVICE AND OPTICAL UNIT INCLUDING OPTICAL DEVICE

An optical device includes a protective cover, a housing, and a vibrating body that vibrates the protective cover by selecting, from multiple vibration modes in which the protective cover is vibrated, a cleaning mode in which vibration displacement of the protective cover becomes maximum and a higher-order heating mode in which the number of nodes is larger than that in the cleaning mode. In the heating mode, the position of the maximum vibration displacement in this vibration mode is within a region of the protective cover that corresponds to the field of view of the optical sensor.