An object is to provide an ultrasound source azimuth determining apparatus that is compact and capable of measuring the azimuth of an ultrasound source over a wide search range at one time while reducing the effect of grating lobes.
An ultrasound source azimuth determining apparatus includes a camera configured to pick up an image of a measured object; an array sensor configured to measure a sound pressure of ultrasound originating from a direction of the measured object; computing means for generating a sound pressure map on the basis of sound pressure information of ultrasound acquired by the array sensor, and superimposing the sound pressure map and a picked-up image acquired by the camera to generate a composite image; and display means for displaying the composite image. The array sensor includes a total of greater than or equal to 9 and less than or equal to 25 surface mount sensors, and at least some of the surface mount sensors are arranged on an X-axis and a Y-axis in the same plane.