This collision determination device includes: an acquisition unit (21) that acquires detection information from a probe device (31) on the basis of reflected waves thereof; a filtering unit (22) thatfilters the detection information; an object information detection unit (23) that uses the filtered detection information to detect the position of an object; an object path estimation unit (24) thatestimates the path of the object on the basis of changes in the position of the detected object; a host vehicle path estimation unit (25) that estimates the path of a host vehicle; a collision determination unit (26) that executes a determination of a collision between the host vehicle and the object; and a vehicle control unit (27) that executes a vehicle control. The path of the object is estimated on the basis of detection information that has been filtered by a collision determination filter. The path of the object is estimated on the basis of detection information that has been filtered by a vehicle control filter. Said filtering is smoothing that suppresses changes in the detection information. The vehicle control filter and the collision determination filter differ in the degree ofsmoothing by which changes in the detection information are suppressed.