A sound source detection apparatus comprising: a plurality of microphones (102, 102A, m1 to m8); a baffle having a first surface and a second surface, the second surface being a surface opposite to the first surface, the plurality of microphones (102, 102A, m1 to m8) being two-dimensionally arrayed and fixed in the first surface, the baffle allowing the plurality of microphones (102, 102A, m1 to m8) to pick up direct sound from a sound source located at a side of the first surface and preventing the plurality of microphones (102, 102A, m1 to m8) from picking up direct sound from a sound source located at a side of the second surface by effecting diffraction of sound waves generated by the sound source located at the side of the second surface, thereby making a phase difference between sound waves arriving at the plurality of microphones (102, 102A, m1 to m8) larger at the side of the second surface than at the side of the first surface, the sound source detection apparatus further comprising a supporting member (103, 103A) that supports the baffle such that the first surface of the baffle forms a predetermined angle with an installation surface on which the sound source detection apparatus is installed, characterized in that the baffle is a circular plate member, in that the relationship (d 0 /COS(θ c)) < d 1 is satisfied, where θ c is the predetermined angle, d 1 is the diameter of the baffle, and d 0 is the maximum distance between the plurality of microphones (102, 102A, m1 to m8) in the direction defined by the angle θ c, and in that the plurality of microphones are arrayed in a part of the baffle that is closer to the center of the baffle than the outer edge of the baffle. a plurality of microphones (102, 102A, m1 to m8); a baffle having a first surface and a second surface, the second surface being a surface opposite to the first surface, the plurality of microphones (102, 102A, m1 to m8) being two-dimensionally arrayed and fixed in the first surface, the baffle allowing the plurality of microphones (102, 102A, m1 to m8) to pick up direct sound from a sound source located at a side of the first surface and preventing the plurality of microphones (102, 102A, m1 to m8) from picking up direct sound from a sound source located at a side of the second surface by effecting diffraction of sound waves generated by the sound source located at the side of the second surface, thereby making a phase difference between sound waves arriving at the plurality of microphones (102, 102A, m1 to m8) larger at the side of the second surface than at the side of the first surface, the sound source detection apparatus further comprising a supporting member (103, 103A) that supports the baffle such that the first surface of the baffle forms a predetermined angle with an installation surface on which the sound source detection apparatus is installed, characterized in that the baffle is a circular plate member, in that the relationship (d 0 /COS(θ c)) < d 1 is satisfied, where θ c is the predetermined angle, d 1 is the diameter of the baffle, and d 0 is the maximum distance between the plurality of microphones (102, 102A, m1 to m8) in the direction defined by the angle θ c, and in that the plurality of microphones are arrayed in a part of the baffle that is closer to the center of the baffle than the outer edge of the baffle.