A subject information acquisition apparatus includes an electromechanical conversion element which receives an elastic wave generated by irradiating with an electromagnetic wave an object in a subject and converts the received elastic wave into an electric signal； a moving device moves the electromechanical conversion element； a signal processing device calculates an image value based on the electric signal. The moving device moves the electromechanical conversion element from a first position to a second position, the electromechanical conversion element receives the elastic wave at the first position and converts the received elastic wave into a first electric signal, and receives the elastic wave at the second position and converts the received elastic wave into a second electric signal； when the electromechanical conversion element is situated at the second position, the signal processing device calculates a first image value at a specified position inside the subject based on the first electric signal.
