To provide a radar detection apparatus which facilitates the surveillance of an interested target enlarged on a display with its display enlarging function fit to a utilizing purpose without any complicated operations.

The apparatus detects the positions of a plurality of targets from radar-detected data, obtains a relative movement quantity of each target from the relative position change to own ship, thereby acquiring/tracking the position of each target, and designates a specified target among the targets being acquired/tracked to display an enlarged region C including the position of the designated target on an enlarged indication area Z within the display screen. The enlarged region C moves with the relative movement of a target number '10'.