To diagnose precise breast cancer without giving pains to a patient.
A photoacoustic mammography apparatus 2 includes a detecting element 30 equipped with a photographing platform 16 on which breast C1 is placed. In the detecting element 30, a plurality of capacity detection type ultrasonic transducers (cMUT) 31 and an emission end surface 33 of the optical fiber 32 are arranged in the shape of a matrix with a predetermined pitch in the XY direction. The optical fiber 32 is placed in the side of a subject H on the photographing platform 16 inclined at a predetermined angle in the X direction, and the emission end surface 33 is pointed to subject H side. The light that is emitted from the emission end surface 33 of the optical fiber 32 of the subject H side reaches not only breast C1 but also the chest wall part C2 in its back. The photoacoustic image that is turned to the imaged from the sound wave includes information of chest wall part C2 as well as breast C1.