PROBLEM TO BE SOLVED: To provide a subject information acquisition device and a subject information acquisition method which can accurately acquire an optical characteristic value in photoacoustic imaging.SOLUTION: A subject information acquisition device has signal processing means 40 comprising: a setting unit 41 for setting a predetermined sensitivity area corresponding to each of a plurality of acoustic wave detection elements e1, e2, e3 on the basis of sensitivity distributions of the plurality of acoustic wave detection elements； an initial sound pressure acquisition unit 42 for acquiring an initial sound pressure in an area of interest without using a detection signal corresponding to the area of interest, which is acquired by the acoustic wave detection element not including the area of interest in the predetermined sensitivity area； a light volume value acquisition unit 43 for acquiring an integrated light volume value in the area of interest on the basis of the detection signal used by the initial sound pressure acquisition unit； and an optical characteristic value acquisition unit 44 for acquiring an optical characteristic value in the area 33 of interest using the initial sound pressure acquired by the initial sound pressure acquisition unit and the integrated light volume value acquired by the light volume value acquisition unit.SELECTED DRAWING: Figure 1
