Disclosed is a sound source detection device 1 which compares information of sound collected by sound collectors 13, 14, 15, and 16 to detect a predetermined sound source. The sound source detection device 1 includes a target determination unit 22 which arranges sound collectors at the same distance from a noise source inside a mobile object to determine a detection-target region of a sound source, and a sound source detection unit 25 which detects the direction of the predetermined sound source using information of sound of the detection-target region determined by the target determination unit 22. Accordingly, the sound source detection unit 25 does not determine sound input to the sound collectors 13, 14, 15, and 16 at the same timing as a detection target, making it possible to eliminate the influence of a noise source other than a sound source inside the mobile object in advance.