An on-vehicle radar device has a transmission section for transmitting a
radio wave to an object, a receive section for receiving the radio wave
reflected by the object, and a processing section for dividing an object
detection range into three or more of a plurality of areas, setting a
threshold of an intensity of the radio wave received for each of the
plurality of areas, and judging the existence of an object by comparing
the intensity of the radio wave and the threshold. This processing
section sets, based on an auto-cruise control mode or pre-crash mode of
the vehicle, a threshold of a part of an area in the object detection
range to be lower than the threshold of the other areas, or changes the
threshold of the detection area according to the object detection status.