STRUCTURE AND PERFORMANCE REDUCTION SUPPRESSION DEVICE

To effectively suppress deterioration in performance of the radar caused by the ice column, provided is a structure for prevent the performance degradation of a radar, the radar is provided below a plate member disposed on an outer surface of a vehicle and irradiating a radio wave toward an outside of the vehicle. The structure is comprising an ice column suppressing part configured to suppressing the formation of the ice column depending from the lower end of the plate member toward an irradiation area of the radio wave.