An ultrasonic imaging apparatus in which ultrasonic tomographic images can be obtained without repeating ultrasonic transmission/reception at many times while sequentially changing the direction of the ultrasonic beam. The ultrasonic imaging apparatus includes: a transmitting and receiving unit for processing reception signals outputted from ultrasonic transducers a sampling unit for generating a reception signal matrix representing ultrasonic echoes from sampling points on a section of the object a conversion matrix calculating unit for calculating a conversion matrix representing weighting information when ultrasonic echoes from plural locations on the section are synthesized an inverse matrix calculating unit for calculating an inverse matrix of the conversion matrix and a sound source information calculating unit for calculating a product of the inverse matrix and the reception signal matrix to obtain a sound source signal matrix representing information on reflective sound sources within the object, and generating an image signal.
