A subject information acquiring apparatus of the present invention includes a probe which has a plurality of elements arranged in an array which receive elastic waves propagating within a subject and converts the received elastic waves to a received signals, a first signal processing unit which uses the received signals output by the elements to calculate a first output signal corresponding to the elastic waves from a target position, a second signal processing unit which uses the first output signal for the target position to calculate a second output signal corresponding to elastic waves from the target position, and an image processing unit which uses the second output signal to generate image data for display. In this case, at least one of the first signal processing unit and the second signal processing unit uses adaptive signal processing to calculate the first output signal or the second output signal.