Provided is a device for detecting intruding objects that enables the detection of intruding objects without requiring antenna switching. Delay units (102) use different delay amounts to delay signals received at each of a plurality of antennas (110). A signal synthesis unit (103) synthesizes the delayed signals. A frequency conversion unit (106) converts the synthesized signal frequency to a baseband. A wave detection unit (107) detects the signal that has undergone frequency conversion. A radar profile generation unit (104) uses the detected signal to generate a profile formed from the distance from the antenna, and the signal strength at each distance from the antenna. A detection processing unit (105) detects a peak in the profile at which the signal strength exceeds a preset threshold value, and determines whether an intruding object is present in a detection region on the basis of the detected peak.