PROBLEM TO BE SOLVED: To provide a subject information acquisition device and a subject information acquisition method by which an image with few artifacts can be obtained by reducing unnecessary signals in photoacoustic imaging in which the prediction of an occurrence place of an acoustic wave and a place of the multiple reflection is difficult to make in advance.SOLUTION: A subject information acquisition device includes a detection means 17 which detects an acoustic wave generated from a subject 15 as a subject is irradiated with light from a light source 11 and outputs a detection signal and a signal processing means 19 which acquires image information of the subject on the basis of the detection signal. The light includes a first light and a second light having a wavelength that is different from the first light. The signal processing means calculates a difference between first data obtained by the emission of the first light and second data obtained by the emission of the second light. The subject information acquisition device reconstructs an image by using the second data.SELECTED DRAWING: Figure 1
